Elastic composition

Abstract

The present disclosure achieves an elastic composition with which displacement of an object can be detected with a simple structure.　The elastic composition is constituted by a rubber composition comprising a base part and protrusions that protrude from a surface of the base part, are distributed along said surface, are magnetized, and are elastically deformed due to an external force.

Description

Elastic composition

[0001] The technology of the present disclosure relates to elastic compositions.

[0002] International Publication No. 2021 / 124992 describes a learning model that is trained using, as training data, at least three physical quantities, including a target physical quantity that changes in response to deformation and that has associated time-series information. This learning model is trained to input at least two physical quantities other than the target physical quantities and output the target physical quantities. The learning model also includes an estimation unit that receives input of two physical quantities to be estimated that correspond to the at least two physical quantities other than the target physical quantities, and estimates the target physical quantity corresponding to the estimation target.

[0003] WO 2021 / 124992 also describes that a component includes a first physical quantity whose electrical properties change in response to deformation and which deforms the component, a second physical quantity representing the electrical properties, and a target physical quantity representing the amount of deformation of the component. WO 2021 / 124992 also describes that a learning model receives the first physical quantity and the second physical quantity as inputs and outputs the target physical quantity.

[0004] The electrical properties described in Patent Document 1 include electrical resistance, and another example is capacitance. However, measuring these electrical properties and capacitance requires wiring, resulting in a complex structure.

[0005] An object of the present disclosure is to obtain an elastic composition that can detect the displacement of an object with a simple structure.

[0006] The elastic composition of the first embodiment has a base and protruding portions that protrude from the surface of the base, are distributed in a direction along the surface, are magnetic, and are elastically deformable by an external force.

[0007] In this elastic composition, the protrusions rising from the surface of the base are distributed in a direction along the surface of the base and are magnetic. This generates a magnetic field around the elastic composition. When the protrusions undergo elastic deformation due to an external force from an object, the surrounding magnetic field also changes, and this change in magnetic field makes it possible to detect the displacement of the object. No wiring is required in the base or protrusions, making this a simple structure.

[0008] In a second aspect, in the elastic composition of the first aspect, the raised portions have a constant cross-sectional shape in a direction parallel to the surface.

[0009] Since the cross-sectional shape of the protrusion is constant (for example, circular) in the direction perpendicular to the protruding direction, the deformed shape of the protrusion is stable.

[0010] In a third aspect, in the elastic composition of the first aspect, the raised portion has a shape including a portion whose cross-sectional area in a direction parallel to the surface decreases toward the tip in the raised direction.

[0011] Therefore, even if the external force acting on the protrusion from the object is small, the magnetic field can be changed by deformation of the protrusion.

[0012] In a fourth aspect, in the elastic composition of any one of the first to third aspects, the raised portion includes a plurality of protrusions spaced apart in a direction along the surface.

[0013] The protrusions included in the raised portion are multiple and are arranged at intervals in a direction along the surface, so that displacement of the object can be detected in the region where the protrusions are arranged.

[0014] In a fifth aspect, in the elastic composition of any one of the first to fourth aspects, the base portion is formed of non-magnetic rubber.

[0015] The non-magnetized base allows for highly accurate detection of the displacement of the object.

[0016] The technology of the present disclosure makes it possible to detect the displacement of an object with a simple structure.

[0017] FIG. 1 is a perspective view showing a rubber composition of a first embodiment. FIG. 2 is an explanatory diagram showing changes in magnetic field lines generated by a rubber composition of an embodiment. FIG. 3 is a plan view showing a rubber composition of the first embodiment. FIG. 4 is a front view showing the rubber composition of the first embodiment together with a shear force measuring device. FIG. 5 is a block diagram showing the configuration of a shear force measuring device for a rubber composition of the first embodiment. FIG. 6 is a front view showing an example of a deformed state of the rubber composition of the first embodiment. FIG. 7 is a front view showing an example of a deformed state of the rubber composition of the first embodiment. FIG. 8 is a front view showing an example of a deformed state of the rubber composition of the first embodiment. FIG. 9 is a front view showing an example of a deformed state of the rubber composition of the first embodiment. FIG. 10 is a front view showing a rubber composition of a second embodiment. FIG. 11 is a front view showing a rubber composition of a third embodiment. FIG. 12 is a front view showing a rubber composition of a fourth embodiment. FIG. 13 is a front view showing a rubber composition of a comparative example. FIG. 14 is a table showing evaluation results of shear force estimation for the rubber compositions of the first to fourth embodiments and the comparative example. FIG. 15 is a perspective view showing a rubber composition of a fifth embodiment. FIG. 16 is a perspective view showing a rubber composition according to the sixth embodiment.

[0018] Hereinafter, an elastic composition according to one embodiment of the present disclosure will be described with reference to the drawings. Components indicated by the same reference numerals in the various drawings are the same components. However, unless otherwise specified in the specification, each component is not limited to one, and may be present in multiple numbers.

[0019] Furthermore, descriptions of overlapping configurations and symbols in each drawing may be omitted. Note that the technology of the present disclosure is not limited to the following embodiments, and can be implemented by making appropriate modifications, such as omitting configurations or replacing them with different configurations, within the scope of the purpose of the technology of the present disclosure.

[0020] 1 shows a rubber composition 12 according to a first embodiment. The rubber composition 12 is an example of an elastic composition. In the drawing, the width direction, depth direction, and thickness direction of the rubber composition 12 are indicated by arrows X, Y, and Z, respectively.

[0021] The rubber composition 12 has a base 14. The base 14 is made of rubber. In the illustrated example, the base 14 is plate-shaped or sheet-shaped and is formed into a rectangular shape when viewed in the thickness direction. One surface of the base 14 in the thickness direction is a front surface 14A, and the opposite surface is a back surface 14B.

[0022] A plurality of protrusions 16 are provided on the surface 14A of the base 14. The protrusions 16 protrude from the surface 14A of the base 14. The protrusions 16 are an example of raised portions. In the first embodiment, the protrusions 16 are cylindrical. As shown in FIG. 2, the protrusions 16 are rectangular in front or side view. When the protrusions 16 are cut in a plane perpendicular to the protruding direction (a plane parallel to the surface 14A), the cross section is circular, and the cross-sectional shape of the protrusions 16 is constant regardless of the cross-sectional position. Furthermore, all of the protrusions 16 have the same shape.

[0023] As shown in FIG. 3 , the multiple protrusions 16 are arranged at regular intervals in a direction along the surface 14A (in-plane direction). The multiple protrusions 16 are distributed in a direction along the surface 14A. Specifically, the protrusions 16 are arranged at regular intervals D1 in the width direction and at regular intervals D2 in the depth direction. In the example shown in FIG. 4 , each row of the protrusions 16 in the depth direction is alternately arranged at positions shifted by half the interval D1 in the width direction. The multiple protrusions 16 are arranged in a so-called staggered arrangement. Furthermore, when focusing on any one protrusion 16, the protrusions 16 located around it are located at any of the vertices of a regular hexagon centered around the protrusion 16 in question.

[0024] Each of the protrusions 16 is made of rubber, similar to the base 14. The protrusions 16 may be formed separately from the base 14 and fixed to the base 14 by welding, adhesive, or other means. In this embodiment, the protrusions 16 are integral with the base 14 and are continuous from the base 14. As shown in FIG. 2 , when an external force is applied from the object BJ to the tip 16T side of the protrusion 16, the protrusion 16 elastically deforms, and the tip 16T is displaced in the width direction and depth direction.

[0025] Each protrusion 16 is magnetic. For example, a predetermined amount of magnetic material (e.g., ferrite powder) is mixed into the rubber to magnetize the protrusions 16. The polarity of the protrusions 16 is not limited; as shown in FIG. 2 , the base end 16R of the protrusion 16 may be an N pole and the tip 16T may be an S pole, or the polarities may be reversed. Furthermore, the protrusions 16 and the base 14 may be magnetized as a whole. In this case, the tip 16T of the protrusion 16 becomes one magnetic pole (e.g., an S pole) and the base 14 becomes the other magnetic pole (e.g., an N pole).

[0026] As shown in FIG. 2 , the protrusions 16 are magnetic, generating a magnetic field around the rubber composition 12 and generating magnetic field lines ML. The spatial distribution of the magnetic field intensity changes as the protrusions 16 deform. This is shown in the lower diagram of FIG. 2 as a change in the shape of the magnetic field lines ML. For example, among the multiple protrusions 16 spaced apart in the width and depth directions, the magnetic field exhibits different changes depending on the position of the deformed protrusions 16. If the degree of deformation varies depending on the position of the protrusions 16, a corresponding change in the magnetic field (spatial change) occurs. Furthermore, if the deformation of the protrusions 16 progresses over time, i.e., if the shape of the protrusions 16 is not constant over time but changes over time, a change in the magnetic field (temporal change) occurs over time. In particular, if the position of the deformed protrusions 16 oscillates over time in the in-plane direction of the surface 14A, the change in the magnetic field also oscillates over time. In this way, the technology disclosed herein makes it possible to grasp not only the deformed positions of the protrusions 16 but also the in-plane distribution and temporal changes of the deformed positions.

[0027] In contrast, the base 14 may or may not be magnetized. For example, if the rubber of the base 14 contains a magnetic material, the base 14 will be magnetized along with the protrusions 16. If the rubber of the base 14 does not contain a magnetic material, the base 14 will not be magnetized even if the protrusions 16 are magnetized.

[0028] In this embodiment, the shear forces acting on the plurality of protrusions 16 are correlated with changes in the magnetic field by a shear force estimation method using a shear force estimation device 20 shown in Figures 4 and 5. The shear forces acting on the protrusions 16 are correlated with the amount of displacement of the tips 16T of the protrusions 16.

[0029] The shear force estimation device 20 has a support base 22 and a shear force sensor 24. In the example shown in Fig. 4, the shear force sensor 24 is disposed on the support base 22. The rubber composition 12 is disposed on the shear force sensor 24. A magnetic force sensor 26 is disposed below the support base 22. The shear force sensor 24 detects the shear force of the protrusion 16 acting from the object BJ.

[0030] As shown in FIG. 5 , the shear force estimation device 20 further includes an estimation unit 28. First input data 30 and second input data 32 are input to the estimation unit 28. The first input data 30 is data indicating the shear force obtained by the shear force sensor 24. The second input data 32 is data indicating the magnetic force obtained by the magnetic force sensor 26. The estimation unit 28 also outputs output data 34. The output data 34 is data indicating the magnitude of deformation of the protrusions 16 of the rubber composition 12 as an estimation result. This output data 34 includes a spatial distribution in the in-plane directions, i.e., in the X-axis direction and the Y-axis direction, and a temporal distribution during the measurement time.

[0031] The estimation unit 28 includes a trained learning model 36. The learning model 36 is a trained model that derives the magnitude of deformation of the protrusions 16 (output data 34) from the shear force of the protrusions of the rubber composition 12 (first input data 30) and the magnetic force around the rubber composition 12 (second input data 32). The learning model 36 is, for example, a model that defines a trained neural network. The learning model 36 is reproduced as a collection of information on the weights (strengths) of connections between nodes (neurons) that make up the neural network.

[0032] When the rubber composition 12 is actually placed at a predetermined target position to detect changes in the magnetic field, a magnetic sensor 26 is placed at a position where the magnetic field change of the rubber composition 12 can be measured, as shown in Fig. 4. In this case, the shear force sensor 24 is not required. That is, as shown in Fig. 5, learning is performed to output the magnitude of deformation of the protrusions 16 as output data 34 from first input data 30 and second input data 32. Therefore, when the rubber composition 12 is actually used, the magnitude of deformation of each of the protrusions 16 can be obtained from the magnetic force obtained by the magnetic sensor 26.

[0033] Next, the operation of this embodiment will be described.

[0034] 6 , in the rubber composition 12 of this embodiment, when an object BJ comes into contact with some or all of the multiple protrusions 16 and the protrusions 16 are deformed, the magnetic field around the rubber composition 12 changes. By detecting the change in the magnetic field lines using the magnetic force sensor 26, it is possible to obtain various pieces of information about the object BJ that has come into contact with the rubber composition 12.

[0035] In the example shown in Figure 6, the rubber composition 12 is installed so that its thickness direction coincides with the vertical direction. As also shown in Figure 3, Figure 6 shows a state in which the object BJ comes into contact with the center of the rubber composition 12 when viewed from above (viewed in the thickness direction). The protrusion 16 is deformed by the contact of the object BJ. The position where the object BJ has come into contact can be determined from the change in the magnetic field that occurs with the deformation of the protrusion 16.

[0036] 6 in particular, when the base 14 is viewed from the front, the two central protrusions 16A are largely deformed, while the surrounding protrusions 16B are less deformed. In this way, when multiple protrusions 16 are deformed, if it can be seen from the spatial distribution of the change in the magnetic field that the amount of deformation differs for each protrusion 16, it is possible to estimate the shape of the object BJ (the shape of the surface facing the rubber composition 12).

[0037] In the example shown in FIG. 7 , the object BJ moves in the direction of arrow M1 within the plane of the base 14. In this case, the deforming protrusions 16 are replaced as the object BJ moves. In the example shown in FIG. 7 , the protrusion 16C is pushed by the object BJ and deforms significantly in the direction of arrow M1. The protrusion 16D next to the protrusion 16C is pushed by the protrusion 16C and deforms. However, the amount of deformation of the protrusion 16D is smaller than that of the protrusion 16C. As the object BJ moves in the direction of arrow M1, the amount of deformation of the protrusion 16C gradually increases, and the amount of deformation of the protrusion 16D also gradually increases. When the amount of movement of the object BJ in the direction of arrow M1 increases further, the object BJ moves away from the protrusions 16C and 16D, as shown in FIG. 8 , and the deformation of the protrusions 16C and 16D is eliminated. Furthermore, the object BJ pushes the protrusion 16E located on the side in the direction of arrow D1. The protrusion 16E and the protrusion 16F pressed by this protrusion 16E are deformed. In this way, by knowing the spatial transition and temporal transition of the deforming protrusion 16, it is possible to know the direction and speed of movement of the object BJ.

[0038] 7 and 8, even if the object BJ moves in the direction opposite to the arrow M1, it is possible to know the direction and speed of this movement. Furthermore, if the object BJ alternately moves in the direction of the arrow M1 and in the opposite direction, it can be estimated that the object BJ is vibrating.

[0039] 9 , the rubber composition 12 is disposed so that its thickness direction (Z-axis direction) is horizontal. An opposing wall 38 is disposed on the surface 14A of the base 14. The rubber composition 12 sandwiches the object BJ between the opposing wall 38 and the rubber composition 12. In this case, the multiple protrusions 16 are deformed, and the amount of deformation of the protrusions 16 varies depending on the position of the protrusions 16 depending on the shape of the object BJ.

[0040] Each of the protrusions 16 has a correlation between the amount of deformation and the elastic force. This correlation may be linear or non-linear. That is, the greater the deformation of the protrusion 16, the greater the elastic force it exerts. Therefore, the total elastic force of the deformed protrusions 16 can be determined from the change in the magnetic field generated by the protrusions 16. This makes it possible to estimate the weight acting on the object BJ, i.e., the mass of the object BJ.

[0041] For example, even when the rubber composition 12 is installed so that its thickness direction coincides with the vertical direction, the greater the mass of the object BJ, the greater the deformation of the protrusion 16. Therefore, even in this case, it is possible to know the mass of the object BJ. In the example shown in Figure 9, compared to the example shown in Figure 6, for example, by sandwiching the object BJ between the opposing wall 38, it is possible to know the mass of the object BJ with high accuracy.

[0042] In the first embodiment, the above example shows a case where the protrusion 16 has a cylindrical shape. The cylindrical protrusion 16 has a constant (circular) cross-sectional shape in a direction perpendicular to the protrusion direction, so the deformed shape of the protrusion 16 is stable. Examples of a shape having a constant cross-sectional shape in a direction perpendicular to the protrusion direction include a cylindrical shape and a polygonal prism shape. However, the shape of the protrusion according to the disclosed technology is not limited to a cylindrical shape or a polygonal prism shape, and examples of the shapes of the protrusions in the various embodiments below can be given. In the following embodiments, elements, components, etc. similar to those in the first embodiment are denoted by the same reference numerals as those in the first embodiment.

[0043] In a rubber composition 42 of a second embodiment shown in Fig. 10, the protrusions 46 have a conical shape. The protrusions 46 are isosceles triangles when viewed from the front or side. When the protrusions 46 are cut along a plane perpendicular to the protruding direction, the cross section is circular, but the cross-sectional area of ​​the protrusions 46 decreases with increasing distance from the base 14. In other words, the protrusions 46 (protruding portions) according to the second embodiment are an example of a shape having a portion in which the cross-sectional area in the direction perpendicular to the protruding direction (protruding direction) decreases toward the tip 46T.

[0044] The protrusion 46 has a shape that tapers (decreases in cross-sectional area) toward the tip 46T. Therefore, even if the external force acting from the object BJ (see FIG. 6, etc.) is small, the tip 46T side is more likely to deform than the cylindrical protrusion 16. In other words, even if the external force acting from the object BJ is small, the protrusion 46 can cause a change in the magnetic field due to deformation of the protrusion 46. In this respect, the protrusion 46 is highly sensitive.

[0045] Furthermore, the base end 46R of the protrusion 46 is thicker than the tip end 46T. In other words, the cross-sectional area increases from the tip end 46T toward the base end 46R. Therefore, when a large external force acts from the object BJ, the base end 46R side is less likely to deform. In other words, the protrusion 46 has a shape that can support a large external force acting from the object BJ.

[0046] In a rubber composition 52 of a third embodiment shown in FIG. 11 , the protrusions 56 are hemispherical on the tip 56T side. In a front or side view, a semicircular shape on the tip 56T side and a rectangular shape on the portion other than the tip 56T appear. A cross section cut along a plane perpendicular to the protruding direction is circular. Furthermore, in the hemispherical portion on the tip 56T side, the cross-sectional area of ​​the protrusion 56 decreases with increasing distance from the base 14. That is, the protrusions 56 (protruding portions) according to the third embodiment are also an example of a shape having a portion in which the cross-sectional area in a direction perpendicular to the protruding direction (protruding direction) decreases toward the tip 56T side. The protrusions 56 according to the third embodiment have a shape that is more easily deformed on the tip 56T side than the cylindrical protrusions 16.

[0047] Furthermore, the protrusion 56 according to the third embodiment has a curved tip 56T without any sharp edges, which makes the protrusion 56 more durable than the protrusion 46 according to the second embodiment, and reduces wear and damage to the tip 16T even after repeated deformation.

[0048] It should be noted that the "shape having a portion in which the cross-sectional area in the direction perpendicular to the protrusion direction decreases toward the tip end in the protrusion direction" in the disclosed technology is not limited to the shapes of the second and third embodiments. For example, the shape may be one in which the cross-sectional area changes stepwise at an intermediate position in the protrusion height of the protrusion.

[0049] A rubber composition 62 of a fourth embodiment shown in Fig. 12 is provided with multiple types of protrusions 16 that differ in protrusion height from a base 14. Specifically, the protrusions 16 have a two-stage cylindrical shape including cylindrical protrusions 16A that protrude relatively high and cylindrical protrusions 16B that protrude relatively low. In the example shown in Fig. 12, the protrusions 16A and the protrusions 16B are arranged alternately in the depth direction (direction of arrow Y).

[0050] In the rubber composition 62 of the fourth embodiment, when the object BJ (see FIG. 6 ) initially contacts the protrusions 16, it contacts the protrusions 16A but not the protrusions 16B. That is, even if the object BJ contacts the protrusion 16A, the protrusions 16B on either side of the protrusion 16A have a low protrusion height, so the object BJ does not contact the protrusions 16A. In this case, compared to a rubber composition having only protrusions of equal protrusion height, the external force from the object BJ is supported with less deformation of the protrusion 16A in the initial stage of contact. Then, as the object BJ moves toward the base 14, it comes into contact with the protrusions 16B in addition to the protrusions 16A, and both the protrusions 16A and 16B deform. This allows for a gradual change in the magnetic field depending on the position of the object BJ.

[0051] 14 shows an example of evaluation results of estimating shear force for rubber compositions having the various protrusion shapes described above, and for a comparative rubber composition 92. The rubber composition 12 of the first embodiment has two configurations: one in which the base 14 is magnetized, and one in which the base 14 is not magnetized. As shown in FIG. 13, the comparative rubber composition 92 does not have protrusions 16, and the surface 14A of the base 14 is flat.

[0052] Each graph in Figure 14 shows the shear force acting on the surface 14A of the base 14 as a function of width or depth position. The horizontal axis of the graph represents width or depth position (unit: mm, millimeters), and the vertical axis represents shear force (unit: N, Newtons). The solid line represents the actual measurement value of the shear force sensor 24 (see Figure 4) in the measurement device shown in Figure 14, and the two-dot chain line represents the estimated value from the value detected by the magnetic force sensor 26 (see Figure 4). The closer the two-dot chain line is to the solid line, the higher the accuracy of the shear force estimation. The NMSE (Normalized Mean Square Error) value shown in Figure 14 is the normalized mean square error between the actual measurement value and the estimated value. The smaller this value, the smaller the deviation between the actual measurement value and the estimated value.

[0053] In the comparative rubber composition 92, the estimated value of shear force is significantly different from the actually measured value, and the NMSE value is also large.

[0054] In contrast, the rubber composition 12 of the first embodiment has cylindrical protrusions 16. The deviation of the estimated value from the measured value for shear force is smaller than in the comparative example. The rubber composition 12 of the first embodiment also has a smaller NMSE value than in the comparative example. In particular, in the case where the base 14 is not magnetized, the NMSE value is smaller than in the case where the base 14 is magnetized.

[0055] In the rubber composition 42 of the second embodiment, the deviation of the estimated value from the measured value for shear force is also smaller than in the comparative example. In particular, in the case of the second embodiment, the NMSE value is smaller than in the other embodiments.

[0056] In the rubber composition 52 of the third embodiment and the rubber composition 62 of the fourth embodiment, the deviation of the estimated value from the measured value for shear force is smaller than in the comparative example, and the NMSE value is also small.

[0057] As described above, it can be seen that, regardless of the shape of the protrusions, an estimated value close to the actually measured value can be obtained for the shear force acting on the rubber composition.

[0058] In the example shown in Figure 14, only the first embodiment is an example in which the base 14 is not magnetized, but in each of the second to fourth embodiments, the base 14 may be configured not to be magnetized.

[0059] In the above embodiments, the protrusions 16, 46, 56, and 66 are exemplified as the raised portions. The raised portions according to the disclosed technology are not limited to the various shapes of the protrusions 16, 46, 56, and 66 described above. For example, they may be protruding walls that protrude from the surface 14A of the base 14 and extend in at least one of the width and depth directions. Examples of such protruding walls include the configurations of the fifth and sixth embodiments shown below.

[0060] 15 , a rubber composition 72 of a fifth embodiment has a plurality of circular protruding walls 76 formed concentrically with respect to a center line CL when the base 14 is viewed in plan view. Each of the protruding walls 76 is difficult to deform in the circumferential direction of a circle centered on the center line CL, but is easy to deform in the radial direction, and in particular, the tip side of the protruding wall 76 is easily collapsed toward the inside in the radial direction.

[0061] Therefore, with the rubber composition 72 of the fifth embodiment, it is easy to detect the shape and displacement of the object BJ located in the vicinity of the center line CL.

[0062] In the rubber composition 72 of the fifth embodiment, there are no particular limitations on the specific configuration of the protruding walls 76, such as the number, thickness, protruding height, and distance (radius) from the center line CL. That is, the specific configuration of the protruding walls 76 can be appropriately set in consideration of the deformation shape of the protruding walls 76 due to expected external forces.

[0063] In a rubber composition 82 of a sixth embodiment shown in FIG. 16 , a plurality of protruding walls 86 are formed in a wave-shaped configuration along the width direction when the base 14 is viewed from above, at regular intervals in the depth direction. In the example shown in FIG. 16 , the wave shape of each protruding wall 86 has a constant amplitude and wavelength, and has a length of three wavelengths in the width direction. There are six protruding walls 86. However, the specific shapes and numbers of the protruding walls 86, such as the amplitude and wavelength, as well as the number and spacing of the protruding walls 86 arranged in the depth direction, are not particularly limited. In the sixth embodiment, the base 14 may or may not be magnetized.

[0064] In the rubber composition 82 of the sixth embodiment, each of the protruding walls 86 is structured such that it is relatively difficult to deform in the extension direction of the waveform (in Figure 16, the width direction of the base 14, the direction of the arrow X), but is easy to deform in a direction perpendicular to this (in Figure 16, the depth direction of the base 14, the direction of the arrow Y).

[0065] Therefore, in the rubber composition 82 of the sixth embodiment, for example, the protruding wall 86 is largely deformed in the depth direction when the base 14 is viewed from above even with a relatively small external force, but is less likely to deform in the width direction when a relatively small external force is applied. In this way, it is possible to vary the detection sensitivity to external forces depending on the orientation of the base 14.

[0066] As in the case shown in FIG. 9 , the rubber composition 82 of the sixth embodiment can be used to sandwich the object BJ between the opposing wall 38 and the rubber composition 82, thereby estimating the mass of the object BJ. In this case, the orientation of the rubber composition 82 (whether the width direction or the depth direction of the base 14 is the vertical direction) is not limited. For example, by arranging the rubber composition 82 so that the alignment direction of the protruding walls 86 (the depth direction of the base 14) coincides with the vertical direction, the mass of the object BJ can be estimated with high sensitivity. Furthermore, by arranging the protruding walls 86 so that the extension direction of the corrugated shape of the protruding walls 86 (the width direction of the base 14) coincides with the vertical direction, the range of masses of the object BJ that can be estimated is widened.

[0067] The rubber composition of the technology of the present disclosure may be applied to any member or device without any particular limitation. That is, the rubber composition may be applied to a member or device that comes into contact with an object BJ (see FIG. 6 , etc.) and detects the displacement of the object by detecting the force acting from the object BJ. As an example, the rubber composition may be applied to the surface of an airbag-type elastic contracting body known as a rubber actuator. In this case, the magnetic force sensor 26 (see FIG. 4 ) that detects changes in the magnetic field may be disposed inside or outside the elastic contracting body.

[0068] In the above, the base 14 is exemplified as being plate-shaped or sheet-shaped, but the shape of the base 14 is not limited to these and may be, for example, block-shaped.

[0069] In the above example, the base 14, the protrusions 16, 46, 56, 66, and the protruding walls 76, 86 are made of rubber, but these elements are not limited to being made of rubber. For example, they may be made of elastic resin (elastomer).

[0070] The disclosure of Japanese Patent Application No. 2023-212481, filed on December 15, 2023, is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard was specifically and individually indicated to be incorporated by reference.

Claims

1. An elastic composition having a base and protruding portions protruding from a surface of the base and distributed in a direction along the surface, the protruding portions being magnetic and elastically deformable in response to an external force.

2. The elastic composition according to claim 1, wherein the raised portion has a constant cross-sectional shape in a direction parallel to the surface.

3. The elastic composition according to claim 1, wherein the raised portion has a shape having a portion whose cross-sectional area in a direction parallel to the surface becomes smaller toward the tip side in the raised direction.

4. The elastic composition of claim 1, wherein said raised portions comprise a plurality of projections spaced apart in a direction along said surface.

5. The elastic composition according to claim 1, wherein said base is formed from a non-magnetic rubber.

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