Cylindrical member for hydraulic actuator

Abstract

To provide a cylindrical member for a hydraulic actuator that has excellent durability.SOLUTION: A cylindrical member for a hydraulic actuator that forms part of a fluid chamber of a hydraulic actuator includes: a cylindrical elastic body; and an elongated body extending along the cylindrical elastic body. The elongated body regulates deformation of the cylindrical elastic body in a longitudinal direction of the elongated body when the cylindrical elastic body deforms with hydraulic pressure of the fluid chamber. The cylindrical elastic body has anisotropy of less likely to extend in the longitudinal direction of the elongated body as compared to a transverse direction of the elongated body in expansion plan view.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present invention relates to a tubular member for a fluid pressure actuator. [Background technology]

[0002] A cylindrical member for a fluid pressure actuator is known which forms part of the fluid chamber of the fluid pressure actuator, the cylindrical member having a cylindrical elastic body and an elongated body extending along the cylindrical elastic body, the elongated body restricting deformation of the cylindrical elastic body in the longitudinal direction of the elongated body when the cylindrical elastic body is deformed by the fluid pressure in the fluid chamber (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-134873 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is preferable that the above-mentioned cylindrical member for a fluid pressure actuator has excellent durability.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a tubular member for a fluid pressure actuator that is excellent in durability. [Means for solving the problem]

[0006] One aspect of the present invention is as follows.

[0007] [1] A cylindrical member for a fluid pressure actuator that forms a part of a fluid chamber of the fluid pressure actuator, A cylindrical elastic body and a long body extending along the cylindrical elastic body, the elongated body restricts deformation of the cylindrical elastic body in a longitudinal direction of the elongated body when the cylindrical elastic body is deformed by the fluid pressure in the fluid chamber, The cylindrical elastic body has anisotropy such that it is less likely to stretch in the longitudinal direction of the elongated body than in the lateral direction of the elongated body when viewed in an exploded view.

[0008] [2] The cylindrical member for a fluid pressure actuator according to [1], wherein the elongated body has a linear shape that forms an angle with respect to the circumferential direction of the cylindrical elastic body when viewed in the developed view.

[0009] [3] The cylindrical member for a fluid pressure actuator according to [2], wherein, when viewed in the developed view, the angle that the elongated body makes with respect to the circumferential direction of the cylindrical elastic body is greater than 0° and less than 45°.

[0010] [4] The anisotropy of the tubular elastic body is such that, when viewed in the unfolded view, the elongated body is less likely to stretch in the longitudinal direction of the imaginary elongated body than in the short direction of the imaginary elongated body that is symmetrical with respect to a line along the axial direction of the tubular elastic body.

[0011] [5] The anisotropy of the cylindrical elastic body is such that, when viewed in the developed view, the cylindrical elastic body is more likely to stretch in the axial direction than in the circumferential direction.

[0012] [6] The anisotropy of the tubular elastic body is such that, when viewed in an expanded view, the angle between the longitudinal direction of the elongated body and the direction in which the tubular elastic body is least stretchable is greater than or equal to 0° and less than 30°.

[0013] [7] The cylindrical member for a fluid pressure actuator according to any one of [3] to [6], wherein the cylindrical elastic body can be deformed into a state in which the cylindrical elastic body is stretched radially outward by 1.5 times or less and stretched axially outward by 4.5 times or more by applying the fluid pressure to the fluid chamber.

[0014] [8] The cylindrical member for a fluid pressure actuator according to [2], wherein the angle that the elongated body makes with respect to the circumferential direction of the cylindrical elastic body when viewed in the developed view is greater than 45° and is not greater than 90°.

[0015] [9] The cylindrical member for a fluid pressure actuator according to [1], wherein the elongated body is annular.

[0016]

[10] the cylindrical elastic body has a cylindrical elastic body main body and a short body group including a plurality of short bodies having a larger elastic modulus than the cylindrical elastic body main body, The cylindrical member for a fluid pressure actuator according to any one of [1] to [9], wherein the group of short bodies has an orientation that determines the anisotropy of the cylindrical elastic body.

[0017]

[11] The cylindrical elastic body has any combination selected from the group consisting of an outer layer that is provided radially outward from the elongated body and has anisotropy that makes it difficult to stretch in the longitudinal direction of the elongated body, an inner layer that is provided radially inward from the elongated body and has anisotropy that makes it difficult to stretch in the longitudinal direction of the elongated body, and an elongated body layer in which the elongated body is embedded. A cylindrical member for a fluid pressure actuator described in any one of [1] to

[10] .

[0018]

[12] A fluid pressure actuator comprising a tubular member for a fluid pressure actuator according to any one of claims [1] to

[11] , wherein the tubular member for a fluid pressure actuator is deformed by applying fluid pressure in the fluid chamber to a peripheral surface of the tubular member for a fluid pressure actuator.

[0019]

[13] A telescopic robot having a plurality of fluid pressure actuators arranged in a honeycomb pattern, each of the fluid pressure actuators having a cylindrical member for a fluid pressure actuator according to any one of [3] to [7] and [9], and wherein the cylindrical member for a fluid pressure actuator is deformed by applying a fluid pressure of the fluid chamber to a peripheral surface of the cylindrical member for a fluid pressure actuator. Effect of the Invention

[0020] According to the present invention, a cylindrical member for a fluid pressure actuator having excellent durability can be provided. [Brief description of the drawings]

[0021] [Figure 1A] 1 is an external view showing a fluid pressure actuator according to a first embodiment of the present invention. [Figure 1B] 2 is a cross-sectional view of the fluid pressure actuator shown in FIG. 1A along the line AA. [Figure 1C] 1B is an external view showing a state of the fluid pressure actuator shown in FIG. 1A before and after pressure is applied. [Figure 1D] 1D is a cross-sectional view of the fluid pressure actuator shown in FIG. 1C. [Figure 2A] FIG. 4 is an external view showing a fluid pressure actuator according to a second embodiment of the present invention. [Figure 2B] 2B is a cross-sectional view of the fluid pressure actuator shown in FIG. 2A. [Figure 2C] 2B is an external view showing a state before and after pressure is applied to the fluid pressure actuator shown in FIG. 2A. [Figure 2D] 2D is an E-E cross-sectional view of the fluid pressure actuator shown in FIG. 2C. [Figure 3A] FIG. 11 is an external view showing a fluid pressure actuator according to a third embodiment of the present invention. [Figure 3B] 3B is a cross-sectional view taken along CC of the fluid pressure actuator shown in FIG. 3A. [Figure 3C] 3B is an external view showing a state before and after pressure is applied to the fluid pressure actuator shown in FIG. 3A. [Figure 3D]3D is a cross-sectional view of the fluid pressure actuator shown in FIG. 3C. [Figure 4] 1B is a development view of the cylindrical member for the fluid pressure actuator shown in FIG. 1A. [Diagram 5] FIG. 1 is an external view showing a telescopic robot according to an embodiment of the present invention. [Figure 6] 1 is an external view showing a mobile robot according to an embodiment of the present invention; [Figure 7] 1 is a graph showing the measurement results of axial elongation in the examples. [Figure 8] 1 is a graph showing the measurement results of the outer diameter increase rate in the examples. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0023] As shown in Figures 1A to 1D and 4, in the first embodiment of the present invention, a tubular member 1 for a fluid pressure actuator is a tubular member 1 for a fluid pressure actuator that forms a part of a fluid chamber 3 of a fluid pressure actuator 2, and has a tubular elastic body 4 and a long body 5 extending along the tubular elastic body 4, and the long body 5 restricts deformation of the tubular elastic body 4 in the longitudinal direction A of the long body 5 when the tubular elastic body 4 is deformed by the fluid pressure in the fluid chamber 3, and the tubular elastic body 4 has anisotropy such that it is less likely to stretch in the longitudinal direction A of the long body 5 than in the short direction of the long body 5 when viewed in an expanded view.

[0024] According to the above configuration, the deformation form when the tubular member 1 for a fluid pressure actuator is operated in response to the fluid pressure of the fluid chamber 3 can be set to a desired form by adjusting the form of the elongated body 5. When the tubular member 1 for a fluid pressure actuator is operated in response to the pressure of the fluid chamber 3, the tubular elastic body 4 is deformed by being pushed out in the pressure direction by the elongated body 5 in the parts where deformation is not restricted (suppressed) by the elongated body 5 every time pressure is applied. From the viewpoint of durability, it is preferable to suppress the above-mentioned deforming by biting. In this regard, when the cylindrical elastic body 4 has anisotropy that makes it harder to stretch in the longitudinal direction A of the long body 5 than in the short direction of the long body 5 when viewed in a developed view as in the above configuration (i.e., the anisotropy of the cylindrical elastic body 4 has a difficult stretch direction B, which is the direction in which it is least stretchable, and is easier to stretch in a direction perpendicular to the difficult stretch direction B, and the angle α between the longitudinal direction A of the long body 5 and the difficult stretch direction B of the cylindrical elastic body 4 is less than 45° as shown in FIG. 4), anisotropic deformation in harmony with the long body 5 is possible even in the parts whose deformation is not restricted by the long body 5, so that the above-mentioned biting deformation can be suppressed. Therefore, according to the above configuration, a cylindrical member 1 for a fluid pressure actuator having excellent durability can be realized. Furthermore, if the above-mentioned biting deformation can be suppressed, the pressure resistance (the magnitude of fluid pressure that can be withstood with one pressurization) can also be improved.

[0025] 4, the elongated body 5 is linear and forms an angle θ with respect to the circumferential direction of the cylindrical elastic body 4 in a developed view. According to the above configuration, by appropriately setting the angle θ that the elongated body 5 forms with respect to the circumferential direction of the cylindrical elastic body 4 in a developed view, it is possible to make the deformation form when the cylindrical member 1 for a fluid pressure actuator is operated in response to the pressure of the fluid chamber 3 into a desired form.

[0026] 4, the angle θ that the long body 5 makes with respect to the circumferential direction of the cylindrical elastic body 4 in the developed view is greater than 0° and less than 45°. According to the above configuration, the long member can make the axial extension of the cylindrical member 1 for a fluid pressure actuator (i.e., the direction along the central axis O of the cylindrical member 1 for a fluid pressure actuator) greater than the radial extension when subjected to fluid pressure. When the angle θ is equal to or less than a predetermined angle, it is possible to configure a fluid pressure actuator 2 in which the cylindrical member 1 for a fluid pressure actuator extends axially outward when subjected to fluid pressure, as described below.

[0027] The anisotropy of the cylindrical elastic body 4 makes it harder to stretch in the longitudinal direction C of the imaginary elongated body 6 (see FIG. 4) than in the short-side direction of the imaginary elongated body 6 symmetrical with respect to a line along the axial direction of the elongated body 5 in a developed view (for example, as shown in FIG. 4, the angle α between the longitudinal direction A of the elongated body 5 and the difficult-to-stretch direction B of the cylindrical elastic body 4 is less than 45° and the angle between the longitudinal direction C of the imaginary elongated body 6 and the difficult-to-stretch direction B of the cylindrical elastic body 4 is less than 45°). According to the above configuration, the anisotropy of the cylindrical elastic body 4 can suppress the twist caused by the spiral elongated body 5 when the cylindrical member 1 for a fluid pressure actuator expands and contracts in the axial direction due to fluid pressure. From this viewpoint, the anisotropy of the cylindrical elastic body 4 may be configured to be least stretchable in the longitudinal direction C of the imaginary elongated body 6 in a developed view.

[0028] The anisotropy of the cylindrical elastic body 4 makes it easier to stretch in the axial direction of the cylindrical elastic body 4 than in the circumferential direction of the cylindrical elastic body 4 when viewed in a developed view. According to the above configuration, the anisotropy of the cylindrical elastic body 4 is less likely to hinder the ease of stretching in the axial direction of the cylindrical member 1 for a fluid pressure actuator when subjected to fluid pressure.

[0029] The anisotropy of the cylindrical elastic body 4 makes it most stretchable in the axial direction of the cylindrical elastic body 4 when viewed in a developed view. According to the above configuration, the anisotropy of the cylindrical elastic body 4 is least likely to hinder the ease of stretching in the axial direction of the cylindrical member 1 for a fluid pressure actuator when subjected to fluid pressure.

[0030] The anisotropy of the cylindrical elastic body 4 is such that the angle α between the longitudinal direction A of the elongated body 5 and the difficult-to-stretch direction B, which is the direction in which the cylindrical elastic body 4 is least stretchable, in a developed view is 0° or more and less than 30°, more preferably 0° or more and less than 20°, and even more preferably 0° or more and less than 10°. As the angle α approaches 0°, the cylindrical elastic body 4 becomes more likely to deform in accordance with the elongated body 5, so that the above configuration can provide good durability (particularly good pressure resistance) and can facilitate axial outward stretching while suppressing radial outward stretching.

[0031] By applying fluid pressure to the fluid chamber 3, the cylindrical elastic body 4 can be deformed to a state in which the radial outward expansion (i.e., the outer diameter increase rate D2 / D1, where D1 is the outer diameter before deformation and D2 is the outer diameter after deformation) is 1.5 times or less (more preferably 1.3 times or less, even more preferably 1.23 times or less, even more preferably 1.2 times or less, even more preferably 1.16 times or less) and the axial outward expansion (i.e., the axial expansion rate L2 / L1, where L1 is the axial length before deformation and L2 is the axial length after deformation) is 4.5 times or more (more preferably 4.98 times or more, even more preferably 5.20 times or more). According to the above configuration, it is possible to realize a fluid pressure actuator 2 that requires deformation of the cylindrical member 1 for a fluid pressure actuator with a large amount of expansion and contraction in the axial direction and a small amount of expansion and contraction in the radial direction. The above configuration is particularly suitable for forming a fluid pressure actuator as an expansion and contraction unit of a mobile robot 14 described later.

[0032] As shown in Figs. 2A to 2D, the angle θ (see Fig. 4) of the long body 5 with respect to the circumferential direction of the cylindrical elastic body 4 in the developed view may be greater than 45° and less than 90°. According to the above-mentioned configuration, the long member can make the tubular member 1 for the fluid pressure actuator stretch more easily in the radial direction than in the axial direction when receiving fluid pressure. In the second embodiment, the angle θ of the long body 5 with respect to the circumferential direction of the cylindrical elastic body 4 in the developed view is 90°. In the second embodiment, the cylindrical member 1 for the fluid pressure actuator has a plurality of long bodies 5 arranged in the circumferential direction over the entire circumference. In Figs. 2A to 2B, only one long body 5 is marked with a symbol. When the angle θ exceeds the predetermined angle, a fluid pressure actuator 2 can be configured in which the cylindrical member 1 for the fluid pressure actuator stretches radially outward while contracting axially inward when receiving fluid pressure, as described later.

[0033] As in the third embodiment of the present invention shown in Figs. 3A to 3D, the long body 5 may be configured to have an annular shape. According to the above configuration, the long member can make the axial stretchability of the tubular member 1 for a fluid pressure actuator larger than the radial stretchability when receiving fluid pressure. In the third embodiment, the tubular member 1 for a fluid pressure actuator has a plurality of long bodies 5 arranged in the axial direction over the entire axial length. In Figs. 3A to 3B, only one long body 5 is labeled. According to this embodiment, it is possible to configure a fluid pressure actuator 2 in which the tubular member 1 for a fluid pressure actuator extends axially outward when receiving fluid pressure, as described later.

[0034] In the third embodiment, the anisotropy of the cylindrical elastic body 4 makes it easier to stretch in the axial direction of the cylindrical elastic body 4 than in the circumferential direction of the cylindrical elastic body 4 when viewed in a developed view. With the above configuration, the anisotropy of the cylindrical elastic body 4 is less likely to impede the ease of stretching in the axial direction of the cylindrical member 1 for a fluid pressure actuator when subjected to fluid pressure.

[0035] In the third embodiment, the anisotropy of the cylindrical elastic body 4 is such that, when viewed in a developed view, it is most stretchable in the axial direction of the cylindrical elastic body 4. According to the above configuration, it is possible to minimize the inhibition by the anisotropy of the cylindrical elastic body 4 of the ease of stretching in the axial direction of the cylindrical member 1 for a fluid pressure actuator when subjected to fluid pressure.

[0036] In each of the above-described embodiments, the cylindrical elastic body 4 has a cylindrical elastic body main body 4a and a short body group 4b consisting of a plurality of short bodies having a higher elastic modulus than the cylindrical elastic body main body 4a, and the short body group 4b has an orientation that determines the anisotropy of the cylindrical elastic body 4. According to the above configuration, a cylindrical elastic body 4 having anisotropy can be realized with a simple structure. The cylindrical elastic body main body 4a can be formed of, for example, rubber or elastomer. The short bodies can be formed of, for example, fiber. The long bodies 5 can be formed of, for example, fiber. The short bodies and the long bodies 5 may be formed of the same material but differ in length, or may be formed of different materials.

[0037] The cylindrical elastic body 4 is preferably configured to have any combination selected from the group consisting of an outer layer 7 that is provided radially outward from the elongated body 5 and has anisotropy that makes it difficult to stretch in the longitudinal direction A of the elongated body 5, an inner layer 8 that is provided radially inward from the elongated body 5 and has anisotropy that makes it difficult to stretch in the longitudinal direction A of the elongated body 5, and an elongated body layer 9 in which the elongated body 5 is embedded. With the above configuration, the biting deformation can be further suppressed. In each of the above-mentioned embodiments, the cylindrical elastic body 4 has the cylindrical outer layer 7, the cylindrical inner layer 8, and the cylindrical elongated body layer 9, but is not limited to this. As in each of the above-mentioned embodiments, the outer layer 7 and the inner layer 8 may each have a short body group 4b and a cylindrical elastic body main body 4a in which the short body group 4b is embedded, and have anisotropy determined by the orientation of the short body group 4b. Although not shown, the elongated body layer 9 may have a elongated body 5 and a cylindrical elastic body 4 in which the elongated body 5 is embedded, the cylindrical elastic body 4 having a short body group 4b and a cylindrical elastic body main body 4a in which the elongated body 5 and the short body group 4b are embedded, and the cylindrical elastic body 4 may have anisotropy determined by the orientation of the short body group 4b. The cylindrical elastic body main body 4a forming the outer layer 7, the inner layer 8, and the elongated body layer 9 may be formed of different materials or may be formed of the same material. Also, the outer layer 7, the inner layer 8, and the elongated body layer 9 may have a cylindrical elastic body main body 4a made of the same continuous material as a whole.

[0038] The fluid pressure actuator 2 preferably has a cylindrical member 1 for a fluid pressure actuator, and is configured to deform the cylindrical member 1 for a fluid pressure actuator by applying the fluid pressure of the fluid chamber 3 to the circumferential surface (inner circumferential surface or outer circumferential surface) of the cylindrical member 1 for a fluid pressure actuator. With the above configuration, a fluid pressure actuator 2 with excellent durability can be realized. In each of the above-mentioned embodiments, the fluid chamber 3 is formed on the radial inside of the cylindrical member 1 for a fluid pressure actuator, and the cylindrical member 1 for a fluid pressure actuator is configured to deform the cylindrical member 1 for a fluid pressure actuator by applying the fluid pressure of the fluid chamber 3 to the inner circumferential surface of the cylindrical member 1 for a fluid pressure actuator, but the present invention is not limited to this.

[0039] In each of the above-described embodiments, the fluid pressure actuator 2 includes the cylindrical member 1 for the fluid pressure actuator, a first end member 10 connected to the first end 1a of the cylindrical member 1 for the fluid pressure actuator, and a second end member 11 connected to the second end 1b of the cylindrical member 1 for the fluid pressure actuator, the first end member 10 having a radial rigidity greater than that of the first end 1a, the second end member 11 having a radial rigidity greater than that of the second end 1b, and the fluid chamber 3 being formed by the cylindrical member 1 for the fluid pressure actuator, the first end member 10, and the second end member 11. According to the above-described configuration, in the case of the first and third embodiments, the fluid pressure actuator 2 can be expanded in the axial direction by pressurizing the fluid chamber 3 (see the two-dot chain line in FIG. 1C for the first embodiment, and the two-dot chain line in FIG. 3C for the third embodiment), and the fluid pressure actuator 2 can be contracted in the axial direction by depressurizing the fluid chamber 3 (see the solid line in FIG. 1C for the first embodiment, and the solid line in FIG. 3C for the third embodiment).

[0040] More specifically, by pressurizing the fluid chamber 3, the fluid pressure acting on one axial side of the plate-shaped first end member 10 covering the first end 1a of the tubular member 1 for the fluid pressure actuator increases, the fluid pressure acting on the other axial side of the plate-shaped second end member 11 covering the second end 1b of the tubular member 1 for the fluid pressure actuator increases, and the radially outward fluid pressure acting on the tubular member 1 for the fluid pressure actuator increases. At that time, the tubular member 1 for the fluid pressure actuator deforms so as to extend axially outward while being restricted from extending in the direction along the elongated body 5, so that the fluid pressure actuator 2 can be extended in the axial direction (see the two-dot chain lines in Figures 1C to 1D for the first embodiment, and see the two-dot chain lines in Figures 3C to 3D for the third embodiment). Furthermore, by reducing the pressure in the fluid chamber 3, the fluid pressure acting on the first end member 10 in one axial direction decreases, the fluid pressure acting on the second end member 11 in the other axial direction decreases, and the fluid pressure acting on the tubular member 1 for the fluid pressure actuator in the radially outward direction decreases. At that time, the tubular member 1 for the fluid pressure actuator deforms so as to contract axially inward while being restricted from elongating in the direction along the elongated body 5, so that the fluid pressure actuator 2 can be contracted in the axial direction (see solid lines in Figures 1C to 1D for the first embodiment, and see solid lines in Figures 3C to 3D for the third embodiment).

[0041] In addition, in the second embodiment, the fluid pressure actuator 2 can be contracted in the axial direction by pressurizing the fluid chamber 3 (see the dotted line in Figure 2C), and the fluid pressure actuator 2 can be expanded in the axial direction by depressurizing the fluid chamber 3 (see the solid line in Figure 2C).

[0042] More specifically, by pressurizing the fluid chamber 3, the fluid pressure acting on one axial side of the plate-shaped first end member 10 covering the first end 1a of the tubular member 1 for the fluid pressure actuator increases, the fluid pressure acting on the other axial side of the plate-shaped second end member 11 covering the second end 1b of the tubular member 1 for the fluid pressure actuator increases, and the fluid pressure acting on the radially outward side of the tubular member 1 for the fluid pressure actuator increases. At that time, the tubular member 1 for the fluid pressure actuator deforms so as to bulge radially outward while being restricted in its extension in the direction along the elongated body 5, so that the fluid pressure actuator 2 can be contracted in the axial direction (see dashed lines in Figures 2C to 2D). Furthermore, by reducing the pressure in the fluid chamber 3, the fluid pressure acting on the first end member 10 in one axial direction decreases, the fluid pressure acting on the second end member 11 in the other axial direction decreases, and the fluid pressure acting on the tubular member 1 for the fluid pressure actuator in the radially outward direction decreases. At that time, the tubular member 1 for the fluid pressure actuator deforms so as to contract radially inward while being restricted from elongating in the direction along the elongated body 5, so that the fluid pressure actuator 2 can be extended in the axial direction (see solid lines in Figures 2C to 2D).

[0043] As shown in FIG. 5, in one embodiment of the present invention, the telescopic robot 12 is a telescopic robot having a plurality of fluid pressure actuators 2 (actuator group 12a) arranged in a honeycomb shape. Each of the fluid pressure actuators 2 has the tubular member 1 for the fluid pressure actuator of the first or third embodiment, and the fluid pressure of the fluid chamber 3 is applied to the inner peripheral surface of the tubular member 1 for the fluid pressure actuator to deform the tubular member 1 for the fluid pressure actuator. More specifically, each of the fluid pressure actuators 2 is the fluid pressure actuator 2 of the first embodiment. According to the above configuration, when each of the fluid pressure actuators 2 is extended in the axial direction, the fluid pressure actuators 2 are buckled due to an external load in a direction compressing the fluid pressure actuator 2 inward in the axial direction, because the adjacent fluid pressure actuators 2 arranged in a honeycomb shape support each other by contacting each other in the radial direction. Note that FIG. 5 shows the telescopic robot 12 in an initial state before extension deformation (before pressure is applied to the fluid chamber 3). The fluid pressure actuator 2 of the third embodiment may be used instead of the fluid pressure actuator 2 of the first embodiment. The actuator group 12a may include a mixture of the fluid pressure actuators 2 of the first embodiment and the fluid pressure actuators 2 of the third embodiment.

[0044] As in this embodiment, the telescopic robot 12 has a first connecting member 12b connected to an end portion of each of the fluid pressure actuators 2 on one axial side (upper side in FIG. 5) and a second connecting member 12c connected to an end portion of each of the fluid pressure actuators 2 on the other axial side (lower side in FIG. 5). The first connecting member 12b has a manifold portion 13. The manifold portion 13 has a supply and discharge flow path 13a for supplying fluid to the fluid chamber 3 and discharging fluid from the fluid chamber 3 through the end portion of each of the fluid pressure actuators 2 on one axial side. The telescopic robot 12 may be configured such that, by supplying fluid to the fluid chamber 3 of each of the fluid pressure actuators 2, each of the fluid pressure actuators 2 extends in the axial direction to expand the axial interval X between the first connecting member 12b and the second connecting member 12c, and, by discharging fluid from the fluid chamber 3 of each of the fluid pressure actuators 2, each of the fluid pressure actuators 2 contracts in the axial direction to reduce the interval X.

[0045] The telescopic robot 12 may have a columnar portion 12d that axially connects the first connecting member 12b and the second connecting member 12c as in this embodiment, and the columnar portion 12d may have a spring portion 12d1 such as a coil spring that extends in the axial direction by elastically deforming when fluid is supplied from the initial state to the fluid chamber 3 of each fluid pressure actuator 2, and then restores its original shape when fluid is discharged from the fluid chamber 3 of each fluid pressure actuator 2. A plurality of columnar portions 12d may be provided as in this embodiment. In this embodiment, four columnar portions 12d are provided, and the columnar portions 12d are disposed at each corner of the first connecting member 12b that is rectangular in top view.

[0046] When using the fluid pressure actuator 2 of the first embodiment, as in this embodiment, the fluid pressure actuator 2 of the first embodiment may be connected to the second connecting member 12c via a bearing 12e that bears a radial load and a thrust load. According to the above configuration, the torsion around the central axis O that occurs in the fluid pressure actuator 2 before and after pressurization can be tolerated by the bearing 12e, making it easier to achieve stable operation.

[0047] As shown in Fig. 6, in one embodiment of the present invention, the mobile robot 14 has a (first) telescopic unit 15a that telescopically expands and contracts in the axial direction, a first expansion / contraction unit 16a that is connected to one end of the telescopic unit 15a and expands and contracts in the radial direction, and a second expansion / contraction unit 16b that is connected to the other end of the telescopic unit 15a and expands and contracts in the radial direction, and the first expansion / contraction unit 16a expands, then the second expansion / contraction unit 16b contracts, then the telescopic unit 15a extends, then the second expansion / contraction unit 16b expands, then the first expansion / contraction unit 16a contracts, then the telescopic unit 15a contracts, and then the first expansion / contraction unit 16a expands, thereby moving inside the piping 17, and the telescopic unit 15a is configured with the fluid pressure actuator 2 of the first embodiment or the third embodiment. According to the above configuration, a mobile robot 14 that can efficiently move inside the piping 17 in the axial direction by utilizing the small outer diameter increase rate and large extension rate of the telescopic unit 15a can be realized. Each of the first expansion / contraction unit 16a and the second expansion / contraction unit 16b is preferably configured with the fluid pressure actuator 2 of the second embodiment.

[0048] As in this embodiment, the mobile robot 14 has a second expansion / contraction unit 15b connected to the other end of the expansion / contraction unit 15a via the second expansion / contraction unit 16b and expanding / contracting in the axial direction, and a third expansion / contraction unit 16c connected to the other end of the expansion / contraction unit 15a via the second expansion / contraction unit 16b and the second expansion / contraction unit 15b and expanding / contracting in the radial direction, and may be configured to move within the piping 17 using the second expansion / contraction unit 15b and the third expansion / contraction unit 16c in addition to the expansion / contraction unit 15a, the first expansion / contraction unit 16a, and the second expansion / contraction unit 16b.

[0049] The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit and scope of the present invention. EXAMPLES

[0050] For the fluid pressure actuator of the first embodiment described above, a number of (four) samples were produced by changing the material of the cylindrical elastic body and the orientation of the short body group, and the axial extension rate (L2 / L1) and the outer diameter increase rate (D2 / D1) of each were measured. Sample 1 had a cylindrical elastic body made of hard rubber, and the short body group (short fibers) were oriented in the circumferential direction. Sample 2 had a cylindrical elastic body made of soft rubber, and the short body group was oriented in the circumferential direction. Sample 3 had a cylindrical elastic body made of soft rubber, and the short body group was oriented parallel to the long body (long fiber). Sample 4 had a cylindrical elastic body made of soft rubber, and the short body group was oriented parallel to the virtual long body (axially symmetrical with the long fiber). The measurement results are shown in Figs. 7 and 8. In Fig. 7, the horizontal axis indicates fluid pressure, and the vertical axis indicates axial extension rate. In Fig. 8, the horizontal axis represents fluid pressure, and the vertical axis represents the rate of increase in outer diameter. As shown in Figs. 7 and 8, sample 2 achieved a maximum axial elongation rate of 4.49 times (at this time, the axial elongation rate was 1.16 times or less). Sample 3 achieved a maximum axial elongation rate of 5.2 times (at this time, the axial elongation rate was 1.23 times or less). [Explanation of symbols]

[0051] 1. Cylindrical member for fluid pressure actuator 1a 1st end 1b 2nd end 2. Fluid Actuator 3 Fluid chamber 4. Cylindrical elastic body 4a Cylindrical elastic body 4b Short body group 5 Long body 6 Virtual long object 7 Outer layer 8 Inner layer 9 Long body layer 10 First end member 11 Second end member 12 Extendable Robot 12a Actuator group 12b First connecting member 12c Second connecting member 12d columnar part 12d1 Spring part 12e bearing 13 Manifold section 13a Supply / discharge channel 14 Mobile Robot 15a First telescopic unit 15b Second telescopic unit 16a First expansion / contraction unit 16b Second expansion / contraction unit 16c 3rd expansion / contraction unit 17 Piping A Longitudinal direction of long object B Difficult to stretch direction C Longitudinal direction of virtual long body O center axis D1 Outer diameter before deformation D2 Outer diameter after deformation L1 Axial length before deformation L2 Axial length after deformation X Spacing α Angle between the longitudinal direction of the long body and the direction of stretch θ is the angle between the elongated body and the circumferential direction of the cylindrical elastic body

Claims

1. A cylindrical member for a fluid pressure actuator that forms a part of a fluid chamber of the fluid pressure actuator, A cylindrical elastic body and a long body extending along the cylindrical elastic body, the elongated body restricts deformation of the cylindrical elastic body in a longitudinal direction of the elongated body when the cylindrical elastic body is deformed by the fluid pressure in the fluid chamber, The cylindrical elastic body has anisotropy such that it is less likely to stretch in the longitudinal direction of the elongated body than in the lateral direction of the elongated body when viewed in an exploded view.

2. 2. The cylindrical member for a fluid pressure actuator according to claim 1, wherein the long body has a linear shape that forms an angle with respect to a circumferential direction of the cylindrical elastic body when viewed in the developed view.

3. 3. The cylindrical member for a fluid pressure actuator according to claim 2, wherein the angle that the elongated body makes with respect to the circumferential direction of the cylindrical elastic body in the developed view is greater than 0° and less than 45°.

4. 4. A cylindrical member for a fluid pressure actuator as described in claim 3, wherein the anisotropy of the tubular elastic body is less likely to stretch in the longitudinal direction of the imaginary elongated body than in the short direction of the imaginary elongated body that is symmetrical with respect to a line along the axial direction of the tubular elastic body when viewed in the unfolded view.

5. 4. The cylindrical member for a fluid pressure actuator according to claim 3, wherein the anisotropy of the cylindrical elastic body is such that, when viewed in the developed view, the cylindrical elastic body is more likely to stretch in an axial direction than in the circumferential direction.

6. 4. The cylindrical member for a fluid pressure actuator according to claim 3, wherein the anisotropy of the cylindrical elastic body is such that, when viewed in an unfolded view, an angle between the longitudinal direction of the elongated body and the direction in which the cylindrical elastic body is least stretchable is greater than 0° and less than 30°.

7. 4. The cylindrical member for a fluid pressure actuator according to claim 3, wherein, by applying the fluid pressure to the fluid chamber, the cylindrical elastic body can be deformed so that it stretches radially outward by 1.5 times or less and stretches axially outward by 4.5 times or more.

8. 3. The cylindrical member for a fluid pressure actuator according to claim 2, wherein the angle that the elongated body makes with respect to the circumferential direction of the cylindrical elastic body in the developed view is greater than 45 degrees and is not greater than 90 degrees.

9. The tubular member for a fluid pressure actuator according to claim 1 , wherein the elongated body is annular.

10. the cylindrical elastic body has a cylindrical elastic body main body and a short body group including a plurality of short bodies having a larger elastic modulus than the cylindrical elastic body main body, 2. The tubular member for a fluid pressure actuator according to claim 1, wherein the group of short members has an orientation that determines the anisotropy of the cylindrical elastic body.

11. 2. The cylindrical elastic body of claim 1, having any combination selected from the group consisting of an outer layer that is provided radially outward from the elongated body and has anisotropy that makes it difficult to stretch in the longitudinal direction of the elongated body, an inner layer that is provided radially inward from the elongated body and has anisotropy that makes it difficult to stretch in the longitudinal direction of the elongated body, and an elongated body layer in which the elongated body is embedded.

12. 2. A fluid pressure actuator comprising the tubular member for a fluid pressure actuator according to claim 1, wherein the tubular member for a fluid pressure actuator is deformed by applying fluid pressure in the fluid chamber to a peripheral surface of the tubular member for a fluid pressure actuator.

13. 4. A telescopic robot having a plurality of fluid pressure actuators arranged in a honeycomb pattern, each of the fluid pressure actuators having the cylindrical member for a fluid pressure actuator according to claim 3, wherein the cylindrical member for a fluid pressure actuator is deformed by applying fluid pressure of the fluid chamber to a peripheral surface of the cylindrical member for a fluid pressure actuator.

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