Linear motion mechanism

Abstract

[Problem] To provide a linear motion mechanism having further enhanced structural strength. [Solution] A linear motion mechanism comprising: an intermediate link that includes a conversion mechanism for converting a rotational force from a motor into a driving force in a linear direction, and is arranged to extend in the linear direction; a first link that, on the basis of the driving force in the linear direction, linearly moves toward a first side in the linear direction from an end of the intermediate link on the first side; and a second link that, on the basis of the driving force in the linear direction, linearly moves toward a second side opposite to the first side, from an end of the intermediate link on the second side. The first link and the second link interlock with each other, and move linearly symmetrically with respect to each other in the linear direction.

Description

[Technical Field]

[0001] The present disclosure relates to a linear motion mechanism. [Background technology]

[0002] In recent years, robotics technology that mimics human movements by electromagnetic or mechanical actions has been developed.

[0003] For example, a linear motion mechanism that expands and contracts in one direction is known as a mechanism for operating the legs or arms of a robot. A linear motion mechanism is required to have a long stroke, be compact and lightweight, and have sufficient strength.

[0004] The following Patent Document 1 discloses a cylindrical coordinate type telescopic shaft operating mechanism that has a vertical shaft that stands upright from a swivel base and a telescopic shaft that extends and retracts in the direction of a horizontal axis perpendicular to the vertical shaft. The telescopic shaft operating mechanism disclosed in Patent Document 1 can perform telescopic operation by extending and retracting the telescopic shaft arm from the telescopic shaft casing. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 3-111196 Summary of the Invention [Problem to be solved by the invention]

[0006] However, the telescopic shaft operating mechanism disclosed in Patent Document 1 has a structurally low strength in the bearing portion of the telescopic shaft arm, making it difficult to apply the telescopic shaft operating mechanism disclosed in Patent Document 1 to applications where impact loads occur, such as the legs of a robot, or to applications for lifting heavy objects, such as cranes.

[0007] Therefore, the present disclosure proposes a new and improved linear motion mechanism that can further increase strength. [Means for solving the problem]

[0008] According to the present disclosure, there is provided a linear motion mechanism including an intermediate link extending in the linear direction, the intermediate link including a conversion mechanism that converts rotational force from a motor into linear driving force, a first link that moves linearly from the first side end of the intermediate link toward a first side in the linear direction based on the linear driving force, and a second link that moves linearly from the second side end of the intermediate link toward a second side opposite to the first side based on the linear driving force, the first link and the second link moving in conjunction with each other and linearly moving symmetrically to each other in the linear direction. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic perspective view showing the configuration of a moving body to which the technology according to the present disclosure is applied; [Figure 2] FIG. 2 is a cross-sectional view showing the configuration of a leg including a linear motion mechanism. [Figure 3] 3 is a cross-sectional view showing the configuration of the leg portion of FIG. 2 as viewed from the A-AA cross section. [Figure 4] FIG. 2 is an explanatory diagram showing a specific configuration of an intermediate link. [Figure 5] FIG. 10 is a cross-sectional view showing the configuration of a leg portion according to a first modified example. [Figure 6] FIG. 10 is a cross-sectional view showing the configuration of a leg portion according to a second modified example. [Figure 7] FIG. 10 is a schematic diagram showing the configuration of an intermediate link of a leg according to a third modified example. [Figure 8] FIG. 10 is a perspective view showing the vicinity of the joint between the leg portion and the main body portion according to a fourth modified example. [Figure 9] FIG. 9 is a cross-sectional view of the locking mechanism shown in FIG. 8 in a fixed state. [Figure 10] FIG. 9 is a cross-sectional view of the locking mechanism shown in FIG. 8 in a free state. [Figure 11] 10A and 10B are schematic diagrams showing the operation of inserting or extracting a key part using a rack and pinion mechanism. [Figure 12] 10A and 10B are schematic diagrams showing the operation of inserting or extracting a key part using a rack and pinion mechanism. [Figure 13] FIG. 11 is a flowchart showing the flow from start to stop of a moving body having legs according to a fourth modified example. [Figure 14] 1 is a schematic diagram illustrating a configuration of a robot arm device including a linear motion mechanism according to an embodiment of the present disclosure. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] Preferred embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0011] The explanation will be given in the following order. 1.Configuration example 1.1. Mobile Configuration 1.2.Configuration of the linear motion mechanism 1.3. Intermediate Link Configuration 2. Variations 2.1. First Variant 2.2. Second Variant 2.3.Third Variant 2.4. Fourth Variant 3. Notes

[0012] <1. Configuration example> (1.1. Configuration of moving body) First, a moving body to which the technology according to the present disclosure is applied will be described with reference to Fig. 1. Fig. 1 is a schematic perspective view showing the configuration of a moving body 1 to which the technology according to the present disclosure is applied.

[0013] As shown in Fig. 1, the moving body 1 includes a main body 12 and multiple legs 11A, 11B, 11C, and 11D. The moving body 1 is, for example, a four-legged robotic device. However, the moving body 1 may also be a three-legged or two-legged robotic device, or a five-legged or more legged robotic device. Hereinafter, the legs 11A, 11B, 11C, and 11D will not be distinguished from one another and will be collectively referred to as legs 11.

[0014] The main body 12 corresponds to the trunk of the moving body 1. The main body 12 is provided with, for example, a control device that controls the overall operation of the moving body 1, various sensor devices that sense the external environment of the moving body 1, and a power supply device that supplies power to each part of the moving body 1.

[0015] The legs 11 are attached to the main body 12, support the main body 12, and are used for walking the mobile body 1. A linear motion mechanism 100 according to an embodiment of the present disclosure is included in at least one of the multiple legs 11. For example, the leg 11 is composed of the linear motion mechanism 100 rotatably attached to the main body 12, and a ground contact part 150 provided at an end of the linear motion mechanism 100.

[0016] The linear motion mechanism 100 is a mechanism that can extend and retract in the extension direction of the leg 11. The linear motion mechanism 100 is configured by connecting multiple links in series, and by sliding the connected multiple links relative to each other, the leg 11 can be extended and retracted in the extension direction. The mobile object 1 can walk using the leg 11 by rotating and extending and retracting the linear motion mechanism 100 included in each leg 11.

[0017] The ground contact part 150 is configured to include wheels 151. The wheels 151 are configured in a disk or cylindrical shape that contacts the running surface at their outer periphery and is rotatable on a rotation axis parallel to the running surface. The wheels 151 are rotated by the drive of a motor, allowing the mobile body 1 to run on the wheels without moving the legs 11.

[0018] The moving body 1 having the above configuration can walk on uneven running surfaces, such as stairs or unpaved roads, by alternately rotating and extending each of the legs 11 without driving the wheels 151. On the other hand, on flat running surfaces such as paved roads, the moving body 1 can run on wheels by driving the wheels 151 while maintaining the posture of each of the legs 11.

[0019] The moving body 1 having the above configuration can extend and retract the legs 11 by the linear motion mechanism 100. Therefore, the moving body 1 having the above configuration can further reduce the height of the moving body 1 when the legs 11 are retracted. Furthermore, the moving body 1 having the above configuration can reduce the risk of interference between the legs 11 and stairs or the like even on uneven ground with large steps, allowing for smoother legged walking.

[0020] (1.2. Structure of the linear motion mechanism) Next, a specific configuration of the linear motion mechanism 100 according to this embodiment will be described with reference to Fig. 2 and Fig. 3. Fig. 2 is a cross-sectional view showing the configuration of the leg portion 11 including the linear motion mechanism 100. Fig. 3 is a cross-sectional view showing the configuration of the leg portion 11 of Fig. 2 as viewed from the A-AA cross section.

[0021] 2 and 3, the linear motion mechanism 100 includes a first link 110, a second link 120, and an intermediate link 130. The ground contact portion 150 including the wheel 151 has been described above, and therefore will not be described here.

[0022] The intermediate link 130 includes a conversion mechanism that converts the rotational force of the motor into linear driving force and is provided to extend in one direction. The linear motion mechanism 100 can extend and retract the first link 110 and the second link 120 in opposite directions based on the driving force generated by the intermediate link 130, thereby enabling multi-stage extension and retraction. By using the intermediate link 130 as a driving unit to extend and retract the first link 110 and the second link 120, the linear motion mechanism 100 can reduce the number of driving force transmission mechanisms, thereby achieving a simplified and lightweight structure. The specific configuration of the intermediate link 130 will be described later.

[0023] The first link 110 is slidably connected to the intermediate link 130. Specifically, the first link 110 has a ground contact portion 150 including a wheel 151 at an end on the ground contact portion 150 side (first side D1), and is connected to the intermediate link 130 at an end on the main body 12 side (second side D2). The first link 110 can slide along the intermediate link 130 toward the first side D1 based on a driving force generated by a conversion mechanism included in the intermediate link 130.

[0024] The second link 120 is slidably connected to the intermediate link 130 on the side opposite to the first link 110. Specifically, the second link 120 has a joint 140 that connects to the main body 12 of the moving body 1 at an end on the main body 12 side (second side D2), and is connected to the intermediate link 130 at an end on the ground contact part 150 side (first side D1). The second link 120 can slide along the intermediate link 130 toward the second side D2 based on a driving force generated by a conversion mechanism included in the intermediate link 130.

[0025] The first link 110 may be connected to the intermediate link 130 at a first surface S1 facing the traveling direction of the moving body 1. The second link 120 may be connected to the intermediate link 130 at a second surface S2 that is opposite to the first surface S1 across the intermediate link 130 and is parallel to the first surface S1.

[0026] For example, when the leg 11 is placed upright perpendicularly on the travel surface, the first surface S1 and the second surface S2 are surfaces whose normal direction is the traveling direction on the travel surface that is perpendicular to the rotation axis direction of the wheel 151. Specifically, the first surface S1 is a surface facing the forward traveling direction of the mobile object 1, and the second surface S2 is a surface facing the backward traveling direction of the mobile object 1.

[0027] This allows the first link 110 and the second link 120 to receive the load applied from the direction of travel when the moving body 1 is walking, at the connection surfaces (first surface S1 and second surface S2) between the first link 110 or the second link 120 and the intermediate link 130. Therefore, the linear motion mechanism 100 can further increase its rigidity against the load applied when the moving body 1 moves forward.

[0028] Furthermore, each of the first link 110 and the second link 120 may have a box-like structure so that the other link can be stored therein. Specifically, the first link 110 may have a box-like structure so that the intermediate link 130 can be stored therein, and the second link 120 may have a box-like structure so that the intermediate link 130 and the first link 110 can be stored therein. In this way, when the linear motion mechanism 100 is contracted, the intermediate link 130 can be stored in the first link 110, and the first link 110 and the intermediate link 130 can be stored in the second link 120, so that the linear motion mechanism 100 can be contracted to a more compact size.

[0029] However, to prevent interference with the second link 120 when the linear motion mechanism 100 is retracted, the first link 110 may be smaller than the box-shaped structure of the second link 120 and may have a box-shaped structure with a partial opening. For example, the first link 110 may be smaller than the box-shaped structure of the second link 120 and may have a box-shaped structure with a second opening on the side opposite to the first opening S1, which is the connecting surface with the intermediate link 130. In this way, by providing the first link 110 with a box-shaped structure with an opening on the side facing the backward direction of the movable body 1, it is possible to reduce the weight of the first link 110 while maintaining rigidity against loads applied when the movable body 1 moves forward. Therefore, the linear motion mechanism 100 can further reduce the weight of the first link 110.

[0030] (1.3. Intermediate Link Configuration) Next, a specific configuration of the intermediate link 130 will be described with reference to Fig. 4. Fig. 4 is an explanatory diagram showing a specific configuration of the intermediate link 130.

[0031] As shown in FIG. 4, the intermediate link 130 includes a power unit 330, a first conversion mechanism 310, a second conversion mechanism 320, a housing 340, a first connecting unit 315, and a second connecting unit 325.

[0032] The first conversion mechanism 310 and the second conversion mechanism 320 are arranged parallel to each other and convert the rotational force from the power unit 330 into driving forces in opposite linear directions. As a result, the first conversion mechanism 310 and the second conversion mechanism 320 can linearly move the first connecting unit 315, to which the first link 110 is connected, and the second connecting unit 325, to which the second link 120 is connected, in opposite directions. Therefore, the first conversion mechanism 310 and the second conversion mechanism 320 can linearly extend and retract the first link 110 and the second link 120 along the intermediate link 130.

[0033] The power unit 330 includes a motor 334 , a motor gear 333 , a first gear 331 , and a second gear 332 .

[0034] The motor 334 is an electric motor that generates a rotational force by converting electrical energy into mechanical energy. The motor 334 may include, for example, a rotor that rotates around an axis, a stator that generates a rotational moment by interacting with the rotor, a rotating shaft that transmits the rotation of the rotor to the outside, and a bearing that supports the rotating shaft.

[0035] The motor gear 333 is a spur gear that rotates due to the rotation of the motor 334. The motor gear 333 is connected to the rotation shaft of the motor 334 and meshes with the first gear 331 and the second gear 332. This allows the motor gear 333 to transmit the rotational force generated by the motor 334 to the first gear 331 and the second gear 332.

[0036] The first gear 331 is a spur gear that meshes with the motor gear 333 and is connected to the first conversion mechanism 310. This allows the first gear 331 to transmit the rotational force generated by the motor 334 to the first conversion mechanism 310, which converts the rotational force into a linear driving force.

[0037] The second gear 332 is a spur gear that meshes with the motor gear 333 and is connected to the second conversion mechanism 320. This allows the second gear 332 to transmit the rotational force generated by the motor 334 to the second conversion mechanism 320, which converts the rotational force into a linear driving force.

[0038] In the power unit 330, by providing the motor gear 333 between the first gear 331 and the second gear 332, it is possible to transmit the rotational force of the motor 334 to the first conversion mechanism 310 and the second conversion mechanism 320 over a shorter distance. This allows the gear diameters and linear velocities of the motor gear 333, the first gear 331, and the second gear 332 to be reduced, making it possible to efficiently transmit the high-speed rotational force from the motor 334 to the first conversion mechanism 310 and the second conversion mechanism 320. Therefore, the power unit 330 can transmit the rotational force from the motor 334 to the first conversion mechanism 310 and the second conversion mechanism 320 using a simpler mechanism, thereby improving the reliability of the linear motion mechanism 100.

[0039] The first conversion mechanism 310 includes a first screw shaft 311, a first linear guide 314, a first bearing 313, and a first linear motion part 312. With this configuration, the first conversion mechanism 310 may include, for example, a ball screw that converts a rotational force into a linear driving force.

[0040] The first screw shaft 311 is coupled to the first gear 331 and is a screw shaft that rotates based on the rotational force from the motor gear 333. The first bearing 313 is provided at the end of the first screw shaft 311 opposite to the end where the first gear 331 is provided, and supports the first screw shaft 311. The first linear motion part 312 is a nut attached to the first screw shaft 311 via a ball, and moves linearly in the axial direction of the first screw shaft 311 as the first screw shaft 311 rotates. In this way, the first conversion mechanism 310 can convert the rotational force from the motor gear 333 into linear motion in the axial direction of the first screw shaft 311 by the first linear motion part 312.

[0041] The first linear guide 314 includes a rail parallel to the axial direction of the first screw shaft 311 and a sliding portion that smoothly moves linearly on the rail in conjunction with the linear motion of the first linear motion portion 312. A first connecting portion 315 provided on the surface of the housing 340 of the intermediate link 130 is connected to the sliding portion of the first linear guide 314. This allows the first connecting portion 315, to which the first link 110 is connected, to slide along the intermediate link 130 in accordance with the linear motion of the sliding portion. Therefore, the first conversion mechanism 310 can slide the first link 110 along the intermediate link 130 based on the rotational force from the motor 334.

[0042] Similar to the first conversion mechanism 310, the second conversion mechanism 320 includes a second screw shaft 321, a second linear guide 324, a second bearing 323, and a second linear motion unit 322. With this configuration, the second conversion mechanism 320 may include, for example, a ball screw that converts a rotational force into a linear driving force.

[0043] The second screw shaft 321 is coupled to the second gear 332 and is a screw shaft that rotates based on the rotational force from the motor gear 333. However, the second screw shaft 321 may be provided parallel to the first screw shaft 311 and have a threading direction opposite to that of the first screw shaft 311. The second bearing 323 is provided at the end of the second screw shaft 321 opposite to the end where the second gear 332 is provided, and supports the second screw shaft 321. The second linear motion unit 322 is a nut attached to the second screw shaft 321 via a ball, and moves linearly in the axial direction of the second screw shaft 321 as the second screw shaft 321 rotates. In this way, the second conversion mechanism 320 can convert the rotational force from the motor gear 333 into linear motion in the axial direction of the second screw shaft 321 by the second linear motion unit 322.

[0044] Here, the first screw shaft 311 and the second screw shaft 321 are provided so that their threading directions are opposite to each other. Therefore, in the first conversion mechanism 310 and the second conversion mechanism 320, the rotational force from the motor gear 333 is converted into driving forces in opposite directions to each other, so that the first linear motion unit 312 and the second linear motion unit 322 can be linearly moved in opposite directions to each other by the same rotational force from the motor gear 333. Therefore, the linear motion mechanism 100 can cause the intermediate link 130, the first link 110, and the second link 120 to perform two-stage extension / contraction movements with a single motor 334.

[0045] The second linear guide 324 includes a rail parallel to the axial direction of the second screw shaft 321 and a sliding portion that smoothly moves linearly on the rail in conjunction with the linear motion of the second linear motion portion 322. A second connecting portion 325 provided on the surface of the housing 340 of the intermediate link 130 is connected to the sliding portion of the second linear guide 324. This allows the second connecting portion 325, to which the second link 120 is connected, to slide along the intermediate link 130 as the sliding portion moves linearly. Therefore, the second conversion mechanism 320 can slide the second link 120 along the intermediate link 130 based on the rotational force from the motor 334.

[0046] The housing 340 contains therein the power unit 330, the first conversion mechanism 310, and the second conversion mechanism 320. Gaps between the housing 340 and the first and second connecting units 315 and 325 are sealed by seals.

[0047] The sealing portion includes a strip seal that covers a gap provided in the housing 340 to linearly move the first connecting portion 315 and the second connecting portion 325, and a magnetic seal that seals the inside of the housing 340 by attracting the strip seal to the housing 340. The first connecting portion 315 and the second connecting portion 325 linearly move while partially peeling off the strip seal attracted by the magnetic seal, thereby minimizing the gaps that occur between the housing 340 and the first connecting portion 315 and the second connecting portion 325. Therefore, the intermediate link 130 can prevent dust from entering the inside of the housing 340, thereby further reducing the possibility of malfunctions in the first conversion mechanism 310 and the second conversion mechanism 320 due to dust.

[0048] In the intermediate link 130 having the above configuration, rotational force from the motor 334 is transmitted to the first threaded shaft 311 and the second threaded shaft 321 via the motor gear 333, the first gear 331, and the second gear 332. The first threaded shaft 311 and the second threaded shaft 321 are threaded in opposite directions, so the first linear motion portion 312 and the second linear motion portion 322 linearly move in opposite directions as the first threaded shaft 311 and the second threaded shaft 321 rotate. As a result, the first link 110 and the second link 120 connected to the first linear motion portion 312 and the second linear motion portion 322 can slide in interlocking motion in opposite directions along the intermediate link 130. Through the above operation, the linear motion mechanism 100 can linearly move the first link 110 and the second link 120 in interlocking motion with each other relative to the intermediate link 130.

[0049] Although the first conversion mechanism 310 and the second conversion mechanism 320 have been described above as including ball screws, the technology according to the present disclosure is not limited to the above example. The first conversion mechanism 310 and the second conversion mechanism 320 may include slide screws instead of ball screws.

[0050] <2. Modifications> Next, first to fifth modified examples of the leg 11 including the linear motion mechanism 100 according to this embodiment will be described with reference to FIGS.

[0051] (2.1. First Modification) FIG. 5 is a cross-sectional view showing the configuration of the leg portion 11 according to the first modified example.

[0052] As shown in FIG. 5, the leg 11 according to the first modified example may further include a first cable carrier 161 and a second cable carrier 162.

[0053] The first cable carrier 161 and the second cable carrier 162 are structural members that can be deformed into any curved structure while maintaining a rigid structure by continuously connecting multiple links that can support wiring at a fine pitch.

[0054] In the leg 11, wiring is provided between the first link 110, the intermediate link 130, and the second link 120 to supply power from the main body 12 to the wheel 151 provided at the tip of the first link 110 and to transmit control commands. However, the wiring provided between the first link 110, the intermediate link 130, and the second link 120 may become tangled with or damaged by other components as it moves with the extension and contraction of the linear motion mechanism 100. Therefore, in the leg 11 according to the first modified example, the wiring provided between the first link 110, the intermediate link 130, and the second link 120 is supported by the first cable carrier 161 and the second cable carrier 162, thereby making it possible to protect the wiring.

[0055] For example, the first cable carrier 161 may support wiring that electrically connects the intermediate link 130 and the first link 110. Furthermore, the second cable carrier 162 may support wiring that electrically connects the intermediate link 130 and the second link 120. In this manner, the first cable carrier 161 and the second cable carrier 162 can be deformed into any curved structure on a plane perpendicular to the rotation axis of the wheel 151 while maintaining a rigid structure. Therefore, the first cable carrier 161 and the second cable carrier 162 can prevent the wiring provided between the first link 110, the intermediate link 130, and the second link 120 from moving unintentionally, thereby protecting the wiring.

[0056] Furthermore, the first cable carrier 161 and the second cable carrier 162 deform within a limited range on a plane perpendicular to the rotation axis of the wheel 151, and therefore can be configured to be stored compactly inside the second link 120 when the leg 11 is contracted. Therefore, the leg 11 according to the first modified example can store the wiring provided between the first link 110, the intermediate link 130, and the second link 120 compactly when the leg 11 is contracted.

[0057] (2.2. Second Modification) FIG. 6 is a cross-sectional view showing the configuration of a leg portion 11 according to a second modified example.

[0058] As shown in FIG. 6, the leg 11 according to the second modified example may further include an elastic portion 170 between the intermediate link 130 and the second link 120.

[0059] The elastic portion 170 includes an elastic member such as a spring, and applies an elastic force between the intermediate link 130 and the second link 120. Specifically, the elastic portion 170 includes a spring and a spring holder provided in the intermediate link 130, and a spring bearing structure provided in the second link 120. When the leg portion 11 contracts, the elastic portion 170 receives the spring in the spring bearing structure and compresses the spring between the intermediate link 130 and the second link, thereby elastically deforming the spring.

[0060] With this, the elastic portion 170 can use the repulsive force of the spring to assist in the extension of the linear motion mechanism 100 when the leg portion 11 is extended after contracting. Also, since the elastic portion 170 is provided so that the spring is elastically deformed only when the leg portion 11 is contracted, even a spring that is short relative to the overall length of the linear motion mechanism 100 can sufficiently assist in the extension of the linear motion mechanism 100.

[0061] Furthermore, the leg 11 according to the second modification may further include the first cable carrier 161 and the second cable carrier 162 described in connection with the leg 11 according to the first modification. In such a case, the elastic portion 170 may be arranged in parallel with the first cable carrier 161 and the second cable carrier 162 on a plane perpendicular to the rotation axis of the wheel 151. This allows the first cable carrier 161, the second cable carrier 162, and the elastic portion 170 to be arranged inside the linear motion mechanism 100 without interfering with each other. Therefore, the leg 11 allows the elastic portion 170, the first cable carrier 161, and the second cable carrier 162 to be arranged inside the linear motion mechanism 100 without interfering with each other, making it possible to more efficiently utilize the internal space of the linear motion mechanism 100.

[0062] (2.3. Third Modification) FIG. 7 is a schematic diagram showing the configuration of an intermediate link 130 of the leg 11 according to a third modified example.

[0063] As shown in FIG. 7, the intermediate link 130 of the leg 11 according to the third modified example may use a chain 343 stretched over a pair of sprockets 341, 342 to linearly move the first linear moving portion 312 and the second linear moving portion 322 in opposite directions.

[0064] Specifically, instead of the power unit 330, the first conversion mechanism 310, and the second conversion mechanism 320, the intermediate link 130 may include a motor 334, a pair of sprockets 341, 342, a chain 343, a first linear guide 314, a second linear guide 324, a first linear motion unit 312, and a second linear motion unit 322.

[0065] The pair of sprockets 341, 342 are mechanical elements such as gears that transmit rotation of the shaft to the chain 343. The chain 343 is stretched between the pair of sprockets 341, 342 under tension, and transmits the rotation of the sprocket 341 as a linear driving force to the first linear motion section 312 and the second linear motion section 322. The chain 343 may be a roller chain or a block chain, or may be a wire or a timing belt. The motor 334 is, for example, a power source that rotates the sprocket 341, and can reciprocate the chain 343 stretched between the pair of sprockets 341, 342.

[0066] First linear motion part 312 is connected to a predetermined position of chain 343, and moves linearly along first linear guide 314 based on the driving force generated by the reciprocating motion of chain 343. First linear guide 314 includes a rail parallel to the arrangement direction of the pair of sprockets 341, 342, and a slide part that can move smoothly on the rail, and causes first linear motion part 312 connected to the slide part to move smoothly linearly along the rail.

[0067] Second linear motion part 322 is connected to a predetermined position of chain 343, and moves linearly along second linear guide 324 based on the driving force generated by the reciprocating motion of chain 343. Second linear guide 324 includes a rail parallel to the arrangement direction of the pair of sprockets 341, 342, and a slide part that can move smoothly on the rail, and causes second linear motion part 322 connected to the slide part to move smoothly linearly along the rail.

[0068] Therefore, by rotating the motor 334 and causing the chain 343 to move back and forth, the intermediate link 130 can move the first linear motion portion 312 and the second linear motion portion 322 connected to the chain 343 linearly in the arrangement direction of the pair of sprockets 341, 342.

[0069] However, the first linear motion portion 312 and the second linear motion portion 322 may be provided on opposite sides of the pair of sprockets 341, 342, for example. For example, when the first linear motion portion 312 is disposed near one sprocket 342, the second linear motion portion 322 may be disposed near the other sprocket 341, across the pair of sprockets 341, 342, so as to be diagonal to the first linear motion portion 312. In this manner, the first linear motion portion 312 and the second linear motion portion 322 move linearly in opposite directions due to the reciprocating motion of the chain 343. Therefore, the first link 110 and the second link 120 connected to the first linear motion portion 312 and the second linear motion portion 322 can slide in opposite directions along the intermediate link 130 in unison.

[0070] According to the intermediate link 130 of the third modification, even when a sprocket and a chain are used instead of a ball screw or a sliding screw, it is possible to cause the first link 110 and the second link 120 to slide in interlocking fashion in opposite directions along the intermediate link 130. The intermediate link 130 of the third modification uses a sprocket and a chain, which are lighter and less expensive than a ball screw or a sliding screw, and therefore the linear motion mechanism 100 can be configured more inexpensively.

[0071] (2.4. Fourth Modification) Fig. 8 is a perspective view showing the vicinity of the connection between leg portion 11 and main body portion 12 according to the fourth modified example. Fig. 9 is a cross-sectional view of locking mechanism 180 shown in Fig. 8 in a fixed state, and Fig. 10 is a cross-sectional view of locking mechanism 180 shown in Fig. 8 in a free state.

[0072] 8, the leg 11 according to the fourth modified example further includes a locking mechanism 180 between the leg 11 and the main body 12. As shown in FIGS. 8 to 10, the locking mechanism 180 includes a keyhole 182 having a keyhole 182H, a key 181, links 183 and 186, a rotating shaft 184, a joint 185, and a solenoid 187.

[0073] Specifically, keyhole portion 182 is provided on the leg portion 11 side, and keyhole portion 182 has keyhole 182H provided on a plane perpendicular to the rotation axis of leg portion 11. Key portion 181 is provided on the main body portion 12 side, and key portion 181 has a rod-shaped structure that can intersect with a plane perpendicular to the rotation axis of leg portion 11. In this way, key portion 181 can fix the rotation angle of leg portion 11 by inserting the rod-shaped structure into keyhole 182H of keyhole portion 182 and preventing rotation of joint portion 140 that connects leg portion 11 and main body portion 12.

[0074] Key part 181 is connected to solenoid 187 via link 183, joint 185, and link 186. Link 183 is provided so as to be rotatable about rotation shaft 184. Solenoid 187 is a self-holding solenoid, and is able to draw in a plunger by the electromagnetic force of solenoid 187 and apply a holding force to the drawn-in plunger.

[0075] For example, as shown in Fig. 9, in the locked state, lock mechanism 180 can rotate link 183 around rotation shaft 184 as an axis by pulling the plunger into solenoid 187. As a result, key portion 181 protrudes so as to intersect with a plane perpendicular to the rotation axis of leg portion 11 and is inserted into keyhole 182H of keyhole portion 182, thereby preventing rotation of joint portion 140 connecting leg portion 11 and main body portion 12. Furthermore, the position of key portion 181 is fixed by the fixing force generated by solenoid 187 being transmitted via links 183 and 186, so that key portion 181 can maintain the state inserted into keyhole 182H.

[0076] 10, in the locking mechanism 180 in the free state, the plunger is not retracted by the solenoid 187, and therefore the key portion 181 does not protrude so as to intersect with a plane perpendicular to the rotation axis of the leg portion 11, and is not inserted into the keyhole 182H of the keyhole portion 182. Therefore, the key portion 181 does not interfere with the rotation of the joint portion 140 that connects the leg portion 11 and the main body portion 12, and the locking mechanism 180 can allow the leg portion 11 to rotate freely with respect to the main body portion 12.

[0077] In the lock mechanism 180, the key part 181 can be inserted into or removed from the keyhole 182H even when another configuration is used instead of the solenoid 187. Figures 11 and 12 are schematic diagrams showing the insertion and removal operation of the key part 181 using a rack and pinion mechanism.

[0078] As shown in FIGS. 11 and 12, the key portion 181 may be inserted into or extracted from a keyhole 182H by a pinion gear 192 and a rack gear 191 that are rotated by a motor.

[0079] Specifically, pinion gear 192 is a small-diameter circular spur gear, and rack gear 191 is a longitudinal member having teeth formed on one surface thereof that mesh with pinion gear 192. Key portion 181 is fixed to rack gear 191 on a surface opposite to the meshing surface of rack gear 191 and pinion gear 192, and is provided slidably along guide 193 on which key portion 181 is placed.

[0080] As a result, when the pinion gear 192 is rotated by the motor, the rack gear 191 that meshes with the pinion gear 192 is moved in a direction parallel to the guide 193. Therefore, the key part 181 fixed to the rack gear 191 is similarly moved in a direction parallel to the guide 193, and is inserted into or pulled out of the keyhole 182H.

[0081] According to the above configuration, the locking mechanism 180 can insert or extract the key portion 181 into or from the keyhole 182H even when a rack-and-pinion mechanism is used instead of the solenoid 187. In such a case, the locking mechanism 180 can fix the rotation angle of the leg portion 11 with a simpler configuration.

[0082] Next, the operation of the locking mechanism 180 in the movable body 1 having the leg parts 11 according to the fourth modified example will be described with reference to Fig. 13. Fig. 13 is a flowchart showing the flow from start-up to stop of the movable body 1 having the leg parts 11 according to the fourth modified example.

[0083] 13, for example, first, power is applied to the moving body 1 (S101). However, when the moving body 1 is in a stopped state, the rotation angle of each of the legs 11 is fixed by the locking mechanism 180. Next, the moving body 1 controls the position of the motor of each joint so that each joint assumes a starting or stopping posture (S102). As a result, the key portion 181 of the locking mechanism 180 of each joint is pulled out from the keyhole 182H, thereby releasing the locking mechanism 180 (S103), and each of the legs 11 becomes rotatable relative to the main body 12 of the moving body 1.

[0084] After the above operations, the moving body 1 shifts to a normal operation mode (S104), and performs operations such as legged walking in the normal operation mode (S105). After that, when the desired operation is completed, the moving body 1 shifts to an end operation mode (S106).

[0085] In the termination operation mode, the movable body 1 controls the position of the motor of each joint so that each joint assumes a starting or stopping posture (S107). As a result, the key 181 of the lock mechanism 180 of each joint is inserted into the keyhole 182H, thereby locking the lock mechanism 180 (S108), and the rotation angle of each leg 11 is fixed relative to the main body 12 of the movable body 1. Thereafter, the power supply to the movable body 1 is cut off (S109).

[0086] By the above operation, the movable body 1 having the legs 11 according to the fourth modification can prevent the legs 11 from spreading out in any direction by fixing the rotation angle of each of the legs 11 with the locking mechanism 180 when power is off. Therefore, the movable body 1 having the legs 11 according to the fourth modification can fix the angle of the legs 11 relative to the main body 12 in an upright state when power is off, thereby making it possible to make the movable body 1 have a compact shape that is more suitable for storage.

[0087] In particular, when the elastic portion 170 described in the second modification is provided on the leg portion 11 of the movable body 1, a repulsive force that tries to extend the leg portion 11 is applied to the leg portion 11 when it is contracted from the elastic portion 170. In such a case, the movable body 1 equipped with the leg portion 11 according to the fourth modification can maintain the leg portion 11 in a contracted state by fixing the angle of the leg portion 11 relative to the main body 12 in an upright state, thereby suppressing the repulsive force from the elastic portion 170 by the weight of the movable body 1. This makes it possible for the movable body 1 equipped with the leg portion 11 according to the fourth modification to easily maintain a compact shape that is more suitable for storage.

[0088] <3. Notes> In the above embodiment, an example has been shown in which the linear motion mechanism 100 is provided in the leg 11 of the moving body 1, but the technology according to the present disclosure is not limited to such an example. For example, the linear motion mechanism 100 may be provided in a robot arm device 2. Fig. 14 is a schematic diagram showing the configuration of a robot arm device 2 including the linear motion mechanism 100 according to this embodiment.

[0089] As shown in FIG. 14, the robot arm device 2 includes a base 20, a first linear link 21, a second linear link 22, and an effector unit .

[0090] The pedestal 20 is a base that supports the robot arm device 2. The pedestal 20 may be fixed to, for example, the floor or wall.

[0091] The first linear motion link 21 is a structural member that includes the linear motion mechanism 100 according to this embodiment and is capable of linear motion in a direction perpendicular to the main surface of the base 20. The first linear motion link 21 may be provided on the base 20 so as to be rotatable about an axis normal to the main surface of the base 20.

[0092] The second linear motion link 22 is a structural member that includes the linear motion mechanism 100 according to this embodiment and is capable of linear motion in a direction perpendicular to the linear motion direction of the first linear motion link 21. The second linear motion link 22 may be connected to the first linear motion link 21 so as to be perpendicular to the linear motion direction of the first linear motion link 21.

[0093] The effector unit 23 includes a gripper for gripping an object, and is provided on the tip side of the second linear link 22. The effector unit 23 of the robot arm device 2 can perform a desired task on an object.

[0094] The robot arm device 2 can further reduce the size of the linear motion mechanism 100 when contracted by applying the linear motion mechanism 100 according to this embodiment to the first linear motion link 21 and the second linear motion link 22. Therefore, the footprint of the robot arm device 2 can be reduced, and the risk of interference between the first linear motion link 21 and the second linear motion link 22 and the outside world can be further reduced.

[0095] Although the preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the technical scope of the present disclosure is not limited to such examples. It is clear that a person skilled in the art of the present disclosure can conceive of various modified or altered examples within the scope of the technical idea described in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure.

[0096] Furthermore, the effects described herein are merely descriptive or exemplary and are not limiting. In other words, the technology according to the present disclosure may achieve other effects that will be apparent to those skilled in the art from the description of this specification, in addition to or in place of the above-described effects.

[0097] The following configurations also fall within the technical scope of the present disclosure. (1) an intermediate link including a conversion mechanism that converts rotational force from the motor into linear driving force, the intermediate link extending in the linear direction; a first link that moves linearly from the first side end of the intermediate link toward a first side in the linear direction based on a driving force in the linear direction; a second link that moves linearly from the end of the second side of the intermediate link toward a second side opposite to the first side based on the driving force in the linear direction; Equipped with a linear motion mechanism in which the first link and the second link move in symmetrical relation to each other in the linear direction in cooperation with each other; (2) the conversion mechanism includes a first ball screw and a second ball screw arranged parallel to each other, the first link moves linearly based on the driving force generated by the first ball screw, The linear motion mechanism according to (1) above, wherein the second link moves linearly based on the driving force generated by the second ball screw. (3) The linear motion mechanism described in (2) above, wherein the first ball screw and the second ball screw convert the same rotational force into the driving force toward the first side and the driving force toward the second side. (4) The linear motion mechanism according to (2) or (3) above, wherein the rotational force is transmitted to the first ball screw and the second ball screw by a spur gear. (5) the conversion mechanism includes a pair of sprockets arranged in the linear direction and a chain wound around the pair of sprockets, The linear motion mechanism according to (1) above, wherein the first link and the second link linearly move symmetrically to each other in the linear direction by the driving force from the chain. (6) The linear motion mechanism according to any one of (1) to (5) above, wherein the first link and the second link linearly move along linear guides included in the intermediate link. (7) the first link and the intermediate link are connected on a first surface, The linear motion mechanism according to any one of (1) to (6) above, wherein the second link and the intermediate link are connected by a second surface that is parallel to the first surface and sandwiches the intermediate link. (8) the intermediate link includes the conversion mechanism therein; The linear motion mechanism according to any one of (1) to (7) above, wherein the interior of the intermediate link is sealed with a seal portion. (9) The linear motion mechanism according to any one of (1) to (8) above, wherein the linear motion mechanism is included in at least one leg of a moving body. (10) the second link is provided with a joint that is connected to a main body of the moving body, The linear motion mechanism according to (9) above, wherein the joint rotates the second link about a rotation axis perpendicular to the linear direction. (11) The linear motion mechanism according to (10) above, further comprising a locking mechanism that fixes a rotation angle between the main body and the second link. (12) The linear motion mechanism according to any one of (9) to (11) above, wherein a ground contact portion including a wheel is provided at the end of the first link on the first side. (13) The linear motion mechanism according to any one of (9) to (12) above, wherein the leg portion expands and contracts due to linear motion of the first link and the second link. (14) The first link has a box-shaped structure with a partial opening, The linear motion mechanism according to (13) above, wherein when the leg portion is contracted, the intermediate link is housed inside the box-shaped structure of the first link. (15) The linear motion mechanism according to (14) above, wherein the first link is configured as the box-shaped structure having at least one open side in the backward direction opposite to the forward direction of the moving body. (16) The linear motion mechanism according to any one of (13) to (15) above, wherein when the leg portions are retracted, the intermediate link and the first link are housed inside the second link. (17) The linear motion mechanism according to (16) above, further comprising an elastic portion that elastically deforms between the intermediate link and the second link when the leg portion is retracted. (18) The linear motion mechanism according to any one of (9) to (17) above, further comprising a cable carrier supporting wiring that electrically connects the intermediate link to the first link or the second link. [Explanation of symbols]

[0098] 1. Mobile 11 Legs 12 Main body 100 Linear motion mechanism 110 Link 1 120 Second Link 130 intermediate links 140 Joints 150 Grounding part 151 Wheels 161 No. 1 Cable Carrier 162 Second Cable Carrier 170 Elastic part 310 First Conversion Mechanism 311 First screw shaft 312 First linear motion section 313 First bearing 314 First Linear Guide 315 1st connection part 320 Second Conversion Mechanism 321 Second screw shaft 322 Second linear motion section 323 Second bearing 324 Second Linear Guide 325 2nd connection part 330 Power section 331 First Gear 332 2nd Gear 333 Motor Gear 334 Motor D1 First side D2 2nd side

Claims

1. an intermediate link including a conversion mechanism that converts rotational force from the motor into linear driving force, the intermediate link extending in the linear direction; a first link that moves linearly from the first side end of the intermediate link toward a first side in the linear direction based on a driving force in the linear direction; a second link that moves symmetrically with the first link from the second-side end of the intermediate link toward a second side opposite to the first side based on the driving force in the linear direction; Equipped with the conversion mechanism includes a first ball screw and a second ball screw arranged parallel to each other; a rotational force from the motor is transmitted to the first ball screw and the second ball screw by a first gear and a second gear, which are respectively engaged with a motor gear connected to a rotation shaft of the motor and disposed with the motor gear sandwiched therebetween; the first ball screw linearly moves the first link based on the driving force directed toward the first side, which is obtained by converting the rotational force transmitted from the first gear; The second ball screw is a linear motion mechanism that linearly moves the second link based on the driving force toward the second side, which is obtained by converting the rotational force transmitted from the second gear.

2. A linear motion mechanism as described in claim 1, wherein the first gear and the second gear are spur gears.

3. The linear motion mechanism according to claim 1 , wherein the first link and the second link move linearly along linear guides included in the intermediate link.

4. the first link and the intermediate link are connected at a first surface, The linear motion mechanism according to claim 1 , wherein the second link and the intermediate link are connected by a second surface that is parallel to the first surface and sandwiches the intermediate link.

5. the intermediate link includes the conversion mechanism therein; The linear motion mechanism according to claim 1 , wherein the interior of the intermediate link is sealed by a seal portion.

6. The linear motion mechanism according to claim 1 , wherein the linear motion mechanism is included in at least one leg of a moving body.

7. the second link is provided with a joint that is connected to a main body of the moving body, The linear motion mechanism according to claim 6 , wherein the joint rotates the second link about a rotation axis perpendicular to the linear direction.

8. The linear motion mechanism according to claim 7 , further comprising a locking mechanism that fixes a rotation angle between the main body and the second link.

9. The linear motion mechanism according to claim 6 , wherein a ground contact portion including a wheel is provided at the end of the first link on the first side.

10. The linear motion mechanism according to claim 6 , wherein the leg portion extends and contracts due to linear motion of the first link and the second link.

11. the first link is configured with a box-shaped structure with a partial opening on one side, 11. The linear motion mechanism according to claim 10, wherein when the legs are retracted, the intermediate link is housed inside the box-shaped structure of the first link.

12. The linear motion mechanism according to claim 10 , wherein the intermediate link and the first link are housed inside the second link when the leg portions are retracted.

13. The linear motion mechanism according to claim 12 , further comprising an elastic portion that elastically deforms between the intermediate link and the second link when the leg portion is contracted.

14. The linear motion mechanism according to claim 6 , further comprising a cable carrier that supports wiring that electrically connects the intermediate link to the first link or the second link.

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