Actuators and robotic joint devices

Abstract

To provide actuators and robotic joint devices that facilitate simplification of structure and control. [Solution] The actuator 1 comprises a fixed member 21, a movable member 22, a support member 5, and a pair of drive units 3 and 4. The support member 5 mechanically connects the fixed member 21 and the movable member 22. The pair of drive units 3 and 4 mechanically connect the fixed member 21 and the movable member 22 and are each extendable and retractable. The pair of drive units 3 and 4 are located within a sector-shaped region with a vertex angle of less than 180 degrees, with the support member 5 as the vertex. The pair of drive units 3 and 4 drive the movable member 22 with at least two degrees of freedom relative to the fixed member 21, with the support member 5 as the pivot point.

Description

【Technical Field】 【0001】 The present disclosure generally relates to actuators and robotic joint devices, and more particularly to actuators and robotic joint devices that can be driven with at least two degrees of freedom. 【Background Art】 【0002】 As a related art, a kinematic mechanism that can drive a movable member (platform) with at least two degrees of freedom using a drive unit composed of a voice coil type linear actuator is known (for example, Patent Document 1). This kinematic mechanism includes three drive units (linear actuators), and drives a movable member supported by a support member (pillar) disposed at the center of these three drive units with the three drive units. 【0003】 In the kinematic mechanism according to the related art, the support member supports the movable member with a magnetic ball joint. Further, both ends of each of the three drive units also constitute a magnetic ball joint, whereby the movable member can move with three degrees of freedom with the support member as a fulcrum. 【Prior Art Documents】 【Patent Documents】 【0004】 【Patent Document 1】 [[ID=2)9]]EP3056228A1 【Summary of the Invention】 【Problems to be Solved by the Invention】 【0005】 However, in the configuration according to the above related art, three drive units are required to realize at least two degrees of freedom (three degrees of freedom), and since these three drive units need to be controlled in a complex manner, the structure and control tend to become complicated. 【0006】 This disclosure is made in view of the above-mentioned reasons and aims to provide actuators and robotic joint devices that are easy to simplify in structure and control. [Means for solving the problem] 【0007】 An actuator according to one aspect of the present disclosure comprises a fixed member, a movable member, a support member, and a pair of drive units. The support member mechanically connects the fixed member and the movable member. The pair of drive units mechanically connect the fixed member and the movable member and are each extendable and retractable. The pair of drive units are located within a sector-shaped region with a vertex angle of less than 180 degrees, with the support member as the vertex. The pair of drive units drive the movable member with at least two degrees of freedom relative to the fixed member, with the support member as the pivot point. 【0008】 A robotic joint device according to one aspect of the present disclosure comprises an actuator, a first member, and a second member. The first member is fixed to the fixed member. The second member is fixed to the movable member. [Effects of the Invention] 【0009】 According to this disclosure, there is an advantage in that it is possible to provide actuators and robotic joint devices that are easy to simplify in structure and control. [Brief explanation of the drawing] 【0010】 [Figure 1] Figure 1 is a perspective view showing the schematic configuration of the actuator according to Embodiment 1. [Figure 2] Figure 2 is a schematic diagram of a robot that uses the same actuator as a robotic joint device. [Figure 3] Figure 3 is a schematic exploded perspective view of the actuator shown above. [Figure 4] Figure 4 shows the main components of the actuator, and is a schematic cross-sectional view taken along the line A1-A1 in Figure 5. [Figure 5] Figure 5 is a schematic plan view of the actuator shown above. [Figure 6] Figure 6 is a schematic right side view showing the operation of the actuator described above. [Figure 7] Figure 7 is a schematic front view showing the operation of the actuator described above. [Figure 8] Figure 8 is a perspective view showing the schematic configuration of the actuator according to Embodiment 2. [Figure 9] Figure 9 is a perspective view showing the schematic configuration of the actuator according to Embodiment 3. [Figure 10] Figure 10 is a perspective view showing the schematic configuration of the actuator according to Embodiment 4. [Figure 11] Figure 11 is a perspective view showing the schematic configuration of the actuator according to Embodiment 5. [Modes for carrying out the invention] 【0011】 (Embodiment 1) (1) Overview The following describes the overview of the actuator 1 according to this embodiment with reference to Figures 1 and 2. The drawings referenced in this disclosure are all schematic diagrams, and the ratios of the size and thickness of each component shown in the figures do not necessarily reflect the actual dimensional ratios. For example, the shapes and dimensions of the fixed member 21 and the movable member 22 in Figures 1 and 2 are merely schematic representations for illustrative purposes and are not intended to limit the design to the shapes and dimensions shown. 【0012】 In this embodiment, for the sake of explanation, the direction of the actuator 1 is defined using the left-right direction D1, the front-back direction D2, and the up-down direction D3 shown in Figure 1. The left-right direction D1, the front-back direction D2, and the up-down direction D3 are orthogonal to each other. However, these directions are not intended to limit the direction of use (direction during use) of the actuator 1. 【0013】 As shown in FIG. 1, the actuator 1 according to this embodiment includes a fixed member 21 and a movable member 22. The actuator 1 drives the movable member 22 with at least two degrees of freedom with respect to the fixed member 21. The actuator 1 is a device that converts some kind of energy, such as electric energy, into kinetic energy to perform mechanical movement. As the driving method of the actuator 1, for example, various driving methods such as an electric type, a hydraulic type, a pneumatic type, or a combination thereof can be adopted. In this embodiment, as an example, the actuator 1 is an electric actuator that is driven by being supplied with electric power and drives the movable member 22 by converting electric energy into kinetic energy. 【0014】 The "degree of freedom" referred to in the present disclosure is a parameter indicating the ease of relative movement between two members (in the actuator 1, the fixed member 21 and the movable member 22), and particularly refers to the number of rotation axes with respect to a rotational operation (rotational movement). For example, when the movable member 22 is driven with "one degree of freedom", the movable member 22 can only perform a rotational operation around one rotation axis. In contrast, when the movable member 22 is driven with "two degrees of freedom", the movable member 22 can perform rotational operations around two rotation axes, and when the movable member 22 is driven with "three degrees of freedom", the movable member 22 can perform rotational operations around three rotation axes. 【0015】 In the actuator 1 according to this embodiment, the degree of freedom of the rotational operation (rotational movement) of the movable member 22 with respect to the fixed member 21 is "at least two degrees of freedom". That is, with respect to the fixed member 21, the movable member 22 is driven with two degrees of freedom, three degrees of freedom, or four degrees of freedom or more. 【0016】 In this embodiment, as an example, the degree of freedom of the actuator 1 is "2", that is, "two degrees of freedom". Specifically, the movable member 22 is configured to be able to perform a rotational operation with two degrees of freedom around a fulcrum P1 with respect to the fixed member 21. That is, the movable member 22 can perform rotational operations around each of two rotation axes (the first rotation axis Ax1 and the second rotation axis Ax2). 【0017】 As used in this disclosure, the "rotation axis" refers to a virtual axis (a straight line) that is the center of the rotational movement of a rotating body (such as the movable member 22). That is, both the first rotation axis Ax1 and the second rotation axis Ax2 are virtual axes without physical entities. Here, both the first rotation axis Ax1 and the second rotation axis Ax2 pass through the fulcrum point P1 and, in a plan view (see FIG. 5), are rotation axes that intersect (orthogonal in this embodiment) with each other. That is, the first rotation axis Ax1 and the second rotation axis Ax2 intersect (are orthogonal) with each other at the fulcrum point P1. 【0018】 As an example, the first rotation axis Ax1 is a straight line along the left-right direction D1, and the second rotation axis Ax2 is a straight line along the front-back direction D2. That is, the movable member 22 rotates about the first rotation axis Ax1, causing both ends in the front-back direction D2 to swing in the up-down direction D3, and rotates about the second rotation axis Ax2, causing both ends in the left-right direction D1 to swing in the up-down direction D3. Hereinafter, the rotation about the first rotation axis Ax1 is called "pitch", and the rotation about the second rotation axis Ax2 is called "roll". That is, the first rotation axis Ax1 is the pitch axis, and the second rotation axis Ax2 is the roll axis. 【0019】 The actuator 1 according to this embodiment is used, for example, as shown in FIG. 2, in a joint device (robot joint device 110) for a robot 100 such as an industrial robot. Examples of the robot 100 include humanoid robots and the like that can perform more complex movements and thus can handle a wider variety of tasks. Such a robot 100 includes a plurality (a large number) of robot joint devices 110 to correspond to human joints. 【0020】 As shown in Figure 2, the robot joint device 110 comprises an actuator 1, a first member 111, and a second member 112. The actuator 1 drives the movable member 22 relative to the fixed member 21 with two or more degrees of freedom (two degrees of freedom in this embodiment), as described above. The first member 111 is fixed to the fixed member 21 of the actuator 1. The second member 112 is fixed to the movable member 22. This makes it possible for the robot joint device 110 to drive the second member 112 relative to the first member 111 with two or more degrees of freedom (two degrees of freedom in this embodiment). 【0021】 Such a robotic joint device 110 has the function of a joint and muscle in the human body, and by driving the actuator 1, it is possible to realize movements such as bending, extending and / or twisting between the first member 111 and the second member 112. In this embodiment, as described above, the actuator 1 is an electric actuator, so by electrically controlling and driving the actuator 1, the robotic joint device 110 can realize movements similar to those of human joints. 【0022】 Furthermore, by equipping the robot 100 with multiple robotic joint devices 110 as described above, the robot 100 can perform complex movements that mimic human movements, for example, and can handle a wider variety of tasks. The multiple robotic joint devices 110 applied to the robot 100 may have the same specifications, or they may include robotic joint devices 110 with different specifications. For example, the robotic joint device 110 used in the elbow of the robot 100 may have a 2-degree-of-freedom actuator 1, and the robotic joint device 110 used in the wrist of the robot 100 may have a 3-degree-of-freedom actuator 1. 【0023】 (2)Details The detailed configuration of the actuator 1 according to this embodiment will be described below with reference to Figures 1 to 7. 【0024】 The actuator 1 includes a fixed member 21 and a movable member 22, as well as a support member 5 and a pair of drive units 3 and 4. The support member 5 mechanically connects the fixed member 21 and the movable member 22. The pair of drive units 3 and 4 mechanically connect the fixed member 21 and the movable member 22. The pair of drive units 3 and 4 are each extendable and retractable. The pair of drive units 3 and 4 are located within a sector-shaped region R1 (see Figure 5) with a vertex angle of less than 180 degrees, with the support member 5 as the vertex. The pair of drive units 3 and 4 drive the movable member 22 with at least two degrees of freedom relative to the fixed member 21, using the support member 5 as a pivot point. In this embodiment, as described above, the actuator 1 has "two degrees of freedom," so the pair of drive units 3 and 4 drive the movable member 22 with "two degrees of freedom" relative to the fixed member 21. 【0025】 In this disclosure, the "vertex" of the sector region R1 refers to the corner having the central angle (vertex angle) of the sector region R1, and indicates the point where the straight sections of the sector region R1 (i.e., the parts corresponding to the radius) intersect. In short, when a sector region R1 with a vertex angle of less than 180 degrees is cut out from a circle centered on the support member 5, the pair of drive units 3 and 4 will be located within this sector region R1. 【0026】 In this configuration, a pair of drive units 3 and 4, located within a sector-shaped region R1 with a vertex angle of less than 180 degrees with the support member 5 as its apex, can drive the movable member 22 with at least two degrees of freedom relative to the fixed member 21, with the support member 5 as the pivot point. This makes it possible to achieve two degrees of freedom with a pair (two) drive units 3 and 4, which has the advantage of simplifying the structure and control compared to related technologies that require three drive units. 【0027】 More specifically, as shown in Figures 1 and 3, in this embodiment, the fixed member 21 and the movable member 22 are plate-shaped members having a thickness in the vertical direction D3. Both the fixed member 21 and the movable member 22 are, for example, made of metal and have a thickness that provides sufficient strength. 【0028】 For example, the fixed member 21 is formed in the shape of a roughly equilateral triangle in a plan view. In other words, the fixed member 21 is formed in the shape of a triangular plate. For example, the movable member 22 is formed in the shape of a roughly circular shape in a plan view. In other words, the movable member 22 is formed in the shape of a disc. 【0029】 The plate-shaped fixed member 21 and the movable member 22 are arranged to face each other with a predetermined distance between them in the vertical direction D3. The movable member 22 is located above the fixed member 21. Here, the fixed member 21 is formed to be slightly smaller than the movable member 22 so that the fixed member 21 fits within the projection plane of the movable member 22. Furthermore, in a plan view, the center position of the fixed member 21 and the center position of the movable member 22 coincide, and the center of the movable member 22 is located directly above the center of the fixed member 21. 【0030】 The support member 5 and the pair of drive units 3 and 4 are located between the fixed member 21 and the movable member 22, and mechanically connect (link) the fixed member 21 and the movable member 22. In other words, the movable member 22 is supported above the fixed member 21 by the support member 5 and the pair of drive units 3 and 4. 【0031】 The support member 5 is formed, for example, in a substantially cylindrical shape with a length in the vertical direction D3. The support member 5 mechanically connects the center of the fixed member 21 and the center of the movable member 22. The support member 5 is, for example, made of metal and has a thickness (diameter) that provides sufficient strength. 【0032】 The lower end of the support member 5, that is, the end on the side of the fixing member 21, is fixed to the fixing member 21 using appropriate joining means such as adhesive, welding, or screws. As a result, the support member 5 is erected on the upper surface of the fixing member 21 (the surface facing the movable member 22) in a state that prevents it from tilting. 【0033】 On the other hand, the upper end of the support member 5, that is, the end on the movable member 22 side, is connected to the movable member 22 by a first joint portion 51 with two or more degrees of freedom. In this embodiment, as an example, the first joint portion 51 has three degrees of freedom. In other words, the support member 5 is connected to the movable member 22 using the first joint portion 51 with three degrees of freedom, in a state that allows it to tilt (rotate) with two or more degrees of freedom to the lower surface of the movable member 22 (the surface facing the fixed member 21). 【0034】 In particular, in this embodiment, the first joint portion 51 is a magnetic ball joint that is magnetically coupled using the magnetic force of a permanent magnet. Specifically, as shown in Figures 3 and 4, the first joint portion 51 includes a spherical ball portion 511 made of a magnetic material and a base portion 512 containing a permanent magnet. The ball portion 511 is attracted to the base portion 512 by magnetic force when it fits into a spherical recess 513 of the base portion 512. As a result, the ball portion 511 is supported in a state in which it can rotate with respect to the base portion 512 with three degrees of freedom. 【0035】 In this embodiment, the ball portion 511 is fixed to the movable member 22 using appropriate joining means such as adhesive, welding, or screws, and the base portion 512 is fixed to one end face (upper end face) of the support member 5 using appropriate joining means such as adhesive, welding, or screws. However, the relationship between the ball portion 511 and the base portion 512 may be reversed, with the base portion 512 being fixed to the movable member 22 and the ball portion 511 being fixed to the support member 5. 【0036】 Each of the pair of drive units 3 and 4 is formed in a substantially cylindrical shape, for example, having a length in the vertical direction D3. Each drive unit 3 and 4 only needs to be able to be driven to extend and retract in the longitudinal direction (vertical direction D3). In this embodiment, each drive unit 3 and 4 is electrically driven to extend and retract in response to a power supply, and can be realized by an appropriate mechanism such as a linear motor, voice coil, or rack and pinion. 【0037】 Here, the pair of drive units 3 and 4 are arranged side by side in the left-right direction D1. In this embodiment, as an example, drive unit 3 is located on the left side and drive unit 4 is located on the right side. 【0038】 The pair of drive units 3 and 4 mechanically connect the two vertices of the fixed member 21 to a pair of connection points set at equidistant from the center of the movable member 22. The pair of drive units 3 and 4 and the support member 5 are arranged in a roughly triangular shape so that they do not lie in a straight line in a plan view. 【0039】 Specifically, as shown in Figure 5, in a plan view, the pair of drive units 3 and 4 are arranged at a 120-degree pitch in the circumferential direction of a virtual circle with the support member 5 as its vertex. In other words, the pair of drive units 3 and 4 and the support member 5 are arranged in an isosceles triangle shape with a vertex angle of 120 degrees in a plan view. As a result, the pair of drive units 3 and 4 are located within a sector region R1 with a vertex angle of less than 180 degrees, with the support member 5 as its vertex. 【0040】 The lower ends of the pair of drive units 3 and 4, that is, the ends on the fixed member 21 side, are connected to the fixed member 21 by joints 31 and 41, each with one degree of freedom. In other words, each drive unit 3 and 4 is connected to the fixed member 21 using joints 31 and 41, each with one degree of freedom, on the upper surface of the fixed member 21 (the surface facing the movable member 22), in a state that allows it to tilt (rotate) with one degree of freedom. 【0041】 In particular, in this embodiment, each joint portion 31, 41 is a hinge structure that is joined so as to be rotatable around a pivot point. Specifically, as shown in Figures 3 and 4, each joint portion 31, 41 allows each drive portion 3, 4 to be tilted toward the center of the fixed member 21 (support member 5) in a plan view. 【0042】 The upper ends of the pair of drive units 3 and 4, that is, the ends on the movable member 22 side, are connected to the movable member 22 by second joints 32 and 42 having two or more degrees of freedom. In this embodiment, as an example, the second joints 32 and 42 have three degrees of freedom. In other words, each drive unit 3 and 4 is connected to the movable member 22 using second joints 32 and 42, each having three degrees of freedom, in a state that allows it to tilt (rotate) with two or more degrees of freedom to the lower surface of the movable member 22 (the surface facing the fixed member 21). 【0043】 In particular, in this embodiment, the second joint portions 32 and 42 are magnetic ball joints that are magnetically coupled using the magnetic force of permanent magnets. Specifically, as shown in Figures 3 and 4, the second joint portion 32 of the drive unit 3 includes a spherical ball portion 321 made of a magnetic material and a base portion 322 including a permanent magnet. The ball portion 321 is attracted to the base portion 322 by magnetic force when it fits into the spherical recess 323 of the base portion 322. As a result, the ball portion 321 is supported in a state in which it can rotate with respect to the base portion 322 with three degrees of freedom. 【0044】 In this embodiment, the ball portion 321 is fixed to one end face (upper end face) of the drive unit 3 using appropriate joining means such as adhesive, welding, or screws, and the base portion 322 is fixed to the movable member 22 using appropriate joining means such as adhesive, welding, or screws. However, the relationship between the ball portion 321 and the base portion 322 may be reversed, with the base portion 322 being fixed to the movable member 22 and the ball portion 321 being fixed to the drive unit 3. 【0045】 The second joint portion 42 of the drive unit 4 has the same configuration as the second joint portion 32 of the drive unit 3. That is, the second joint portion 42 includes a spherical ball portion 421 made of a magnetic material and a base portion 422 including a permanent magnet. The ball portion 421 is fixed to one end face (upper end face) of the drive unit 4 using appropriate joining means such as adhesive, welding, or screws, and the base portion 422 is fixed to the movable member 22 using appropriate joining means such as adhesive, welding, or screws. 【0046】 Here, the pair of drive units 3 and 4 can be extended and retracted individually. For example, it is possible to extend drive unit 3 while retracting drive unit 4. It is also possible to extend or retract both of the pair of drive units 3 and 4 simultaneously. 【0047】 According to the configuration described above, the pair of drive units 3 and 4 make it possible to drive the movable member 22 with at least two degrees of freedom relative to the fixed member 21. In this embodiment, since the movable member 22 is supported by the support member 5 at the first joint portion 51, it is rotationally driven around the first rotation axis Ax1 and the second rotation axis Ax2, with the first joint portion 51 as the pivot point. 【0048】 More precisely, since the first joint 51 is a (magnetic) ball joint, the movable member 22 rotates with two degrees of freedom, with the center of the sphere constituting the ball portion 511 in the first joint 51 as the pivot point P1. In other words, as shown in Figure 5, the movable member 22 is rotationally driven by a pair of drive units 3 and 4, each centered on two rotation axes (first rotation axis Ax1 and second rotation axis Ax2) that pass through the pivot point P1 and intersect each other (orthogonal in this embodiment). 【0049】 Specifically, as shown in Figure 6, the movable member 22 performs a pitch motion, rotating around the first rotation axis Ax1, as the pair of drive units 3 and 4 extend and retract simultaneously. In other words, the movable member 22 rotates around the first rotation axis Ax1 as the drive units 3 and 4 extend synchronously so that they are always the same length. For example, as the pair of drive units 3 and 4 retract simultaneously, the movable member 22 rotates counterclockwise in Figure 6, such that the front end of the movable member 22 descends and the rear end of the movable member 22 rises. Conversely, as the pair of drive units 3 and 4 extend simultaneously, the movable member 22 rotates clockwise in Figure 6, such that the front end of the movable member 22 rises and the rear end of the movable member 22 descends. 【0050】 As the movable member 22 moves in a pitching motion, the coupling position of the pair of drive units 3 and 4 with respect to the movable member 22 (i.e., the position of the second joints 32 and 42) changes in a plan view. Therefore, as the movable member 22 moves in a pitching motion, each drive unit 3 and 4 tilts relative to the fixed member 21 with the joints 31 and 41 as pivot points. 【0051】 On the other hand, as shown in Figure 7, the movable member 22 performs a rolling motion around the second rotation axis Ax2 by extending and retracting the pair of drive units 3 and 4 so that there is a difference in the lengths of the pair of drive units 3 and 4. In other words, the movable member 22 rotates around the second rotation axis Ax2 by extending the drive units 3 and 4 so that they are of different lengths. For example, as the left drive unit 3 retracts and the right drive unit 4 extends, the movable member 22 rotates counterclockwise in Figure 7 so that the left end of the movable member 22 descends and the right end of the movable member 22 rises. Conversely, as the left drive unit 3 extends and the right drive unit 4 retracts, the movable member 22 rotates clockwise in Figure 7 so that the left end of the movable member 22 rises and the right end of the movable member 22 descends. 【0052】 As the movable member 22 rolls, the coupling position of the pair of drive units 3 and 4 with respect to the movable member 22 (i.e., the position of the second joints 32 and 42) changes in a plan view. Therefore, as the movable member 22 rolls, each drive unit 3 and 4 tilts relative to the fixed member 21 with the joints 31 and 41 as pivot points. 【0053】 Furthermore, depending on the control of the pair of drive units 3 and 4, it is also possible to perform a combined pitch and roll motion. In other words, by simultaneously extending and retracting the pair of drive units 3 and 4, and by creating a difference in the amount of extension and retraction of the pair of drive units 3 and 4, the movable member 22 can perform a combined pitch and roll motion. 【0054】 For example, if both the pair of drive units 3 and 4 are retracted, and the amount of retraction of drive unit 3 is greater than the amount of retraction of drive unit 4, the movable member 22 rotates counterclockwise (pitch motion) as shown in Figure 6 and also rotates counterclockwise (roll motion) as shown in Figure 7. Also, if both the pair of drive units 3 and 4 are extended, and the amount of extension of drive unit 3 is greater than the amount of extension of drive unit 4, the movable member 22 rotates clockwise (pitch motion) as shown in Figure 6 and also rotates clockwise (roll motion) as shown in Figure 7. 【0055】 As explained above, depending on the coupling structure (joint portion) of the support member 5 and / or the pair of drive units 3,4 with respect to the fixed member 21 and the movable member 22, and the positional relationship between the support member 5 and the pair of drive units 3,4, an actuator 1 with two or more degrees of freedom (two degrees of freedom in this embodiment) can be realized. In other words, depending on the control of the pair of drive units 3,4, the actuator 1 can drive the movable member 22 with two or more degrees of freedom (two degrees of freedom in this embodiment) while maintaining the center of rotation at a single point (fulcrum P1), even with only a pair (two) of drive units 3,4. 【0056】 Furthermore, since the rotation center of the movable member 22 is fixed to the pivot point P1, the calculation of the positioning of the movable member 22 is relatively easy, and the processing time for controlling the pair of drive units 3 and 4 to bring the movable member 22 to the desired position can be relatively short. 【0057】 Here, the range of motion of the movable member 22 in the actuator 1 is determined by the positional relationship between the pivot point P1 (support member 5) and the pair of drive units 3 and 4, the range of motion (extension and retraction) of each drive unit 3 and 4, the range of motion of the first joint 51 and the second joint units 32 and 42, and the range of motion of the joint units 31 and 41, etc. 【0058】 Furthermore, the load capacity (maximum tensile load) of the actuator 1 is determined by the load capacity (maximum tensile load) of the first joint portion 51 and the second joint portions 32 and 42. In this embodiment, since both the first joint portion 51 and the second joint portions 32 and 42 are magnetic ball joints, it is possible to increase the load capacity (maximum tensile load) of the actuator 1 depending on the magnitude of the magnetic attractive force of each magnetic ball joint. As an example, the load capacity (maximum tensile load) of the actuator 1 is set to approximately 6 kg, 8 kg, or 10 kg. 【0059】 Thus, the support member 5 has a first joint portion 51 with two or more degrees of freedom at at least one end in the longitudinal direction. In this embodiment, as an example, the support member 5 has a first joint portion 51 with two or more degrees of freedom only at one end (upper end) on the side of the movable member 22 in the longitudinal direction (vertical direction D3). 【0060】 As a result, the movable member 22 is supported by the support member 5 relative to the fixed member 21, while still being able to move with two or more degrees of freedom. Therefore, it is possible to increase the load-bearing capacity (maximum tensile load) between the fixed member 21 and the movable member 22. 【0061】 Here, the first joint 51 is a magnetic ball joint. Therefore, the magnetic attraction force of the first joint 51 makes it possible to increase the load-bearing capacity (maximum tensile load) between the fixed member 21 and the movable member 22. Furthermore, compared to joints with two or more degrees of freedom other than magnetic ball joints, such as universal joints or spherical bearings, the structure of the first joint 51 can be simplified, and a wide range of motion (movable range) can be easily achieved. 【0062】 Furthermore, each of the pair of drive units 3 and 4 has a second joint portion 32 or 42 with two or more degrees of freedom at at least one end in the longitudinal direction. In this embodiment, as an example, each of the pair of drive units 3 and 4 has a second joint portion 32 or 42 with two or more degrees of freedom only at one end (upper end) on the movable member 22 side in the longitudinal direction (vertical direction D3). 【0063】 As a result, the movable member 22 is supported by a pair of drive units 3 and 4 relative to the fixed member 21, while still allowing movement of two or more degrees of freedom. Therefore, it is possible to increase the load-bearing capacity (maximum tensile load) between the fixed member 21 and the movable member 22. 【0064】 (3) Variant Embodiment 1 is merely one of many reference examples provided in this disclosure. Embodiment 1 can be modified in various ways depending on the design, etc., as long as it achieves the objectives of this disclosure. Furthermore, the drawings referenced in this disclosure are all schematic diagrams, and the ratios of the size and thickness of each component shown in the drawings do not necessarily reflect the actual dimensional ratios. The following lists some modifications of Embodiment 1. The modifications described below can be combined and applied as appropriate. 【0065】 The support member 5 only needs to have a first joint portion 51 with two or more degrees of freedom at at least one end in the longitudinal direction. For example, the support member 5 may have a first joint portion 51 with two or more degrees of freedom at the end (lower end) on the fixing member 21 side in the longitudinal direction (up and down direction D3), or at both ends in the longitudinal direction. 【0066】 Furthermore, each of the pair of drive units 3 and 4 only needs to have a second joint portion 32 or 42 with two or more degrees of freedom at at least one end in the longitudinal direction. For example, each drive unit 3 or 4 may have a second joint portion 32 or 42 with two or more degrees of freedom at the end (lower end) on the fixing member 21 side in the longitudinal direction (vertical direction D3), or at both ends in the longitudinal direction. 【0067】 Furthermore, joints with two or more degrees of freedom, such as the first joint portion 51 and the second joint portions 32 and 42, are not limited to magnetic ball joints, but may also be, for example, universal joints or spherical bearings. 【0068】 Furthermore, joints with one degree of freedom, such as joints 31 and 41, are not limited to hinge structures, but may also be, for example, deep groove ball bearings or angular contact ball bearings. 【0069】 Furthermore, the material of each component of the actuator 1, such as the fixed member 21 and the movable member 22, is not limited to metal; for example, it may be a resin such as engineering plastic. 【0070】 Furthermore, it is not necessary for the support member 5 to be a separate component from the fixing member 21; the support member 5 and the fixing member 21 may be a single, integrated part. 【0071】 Furthermore, lubricants such as lubricating oil or grease may be injected into the movable parts such as the first joint portion 51, the second joint portions 32 and 42, and the joint portions 31 and 41. 【0072】 (Embodiment 2) As shown in Figure 8, the actuator 1A according to this embodiment differs from the actuator 1 according to Embodiment 1 in that the joint portions 31 and 41 at the lower ends of the pair of drive units 3 and 4, that is, the ends on the fixed member 21 side, are "second joint portions" with two or more degrees of freedom. Hereinafter, components similar to those in Embodiment 1 will be denoted by common reference numerals and their descriptions will be omitted as appropriate. 【0073】 In other words, each of the pair of drive units 3 and 4 has a second joint with two or more degrees of freedom at both ends in the longitudinal direction (vertical direction D3). In this embodiment, as an example, the joints 31 and 41 are magnetic ball joints that are magnetically coupled using the magnetic force of permanent magnets. As a result, there are no joints with only one degree of freedom in the pair of drive units 3 and 4. 【0074】 In the actuator 1A according to this embodiment, the movable member 22 is capable of rotational movement with "three degrees of freedom" around the pivot point P1. In other words, the pair of drive units 3 and 4 enable the movable member 22 to rotate around the first rotation axis Ax1 (pitch movement) and the second rotation axis Ax2 (roll movement), as well as rotating around the third rotation axis Ax3. 【0075】 The third axis of rotation Ax3 is a straight line that passes through the pivot point P1 and intersects (orthogonally in this embodiment) both the first axis of rotation Ax1 and the second axis of rotation Ax2, that is, a straight line along the vertical direction D3. Therefore, rotation around the third axis of rotation Ax3 is a "yaw" motion, and the third axis of rotation Ax3 is the yaw axis. 【0076】 Thus, in the actuator 1A according to this embodiment, the pair of drive units 3 and 4 drive the movable member 22 with three degrees of freedom relative to the fixed member 21, with the support member 5 as the pivot point. Therefore, the actuator 1A can achieve a wider variety of movements. 【0077】 Furthermore, the joint sections 31 and 32 with two or more degrees of freedom are not limited to magnetic ball joints, but may also be, for example, universal joints or spherical bearings. 【0078】 The configuration of Embodiment 2 (including modified versions) can be adopted in appropriate combination with the various configurations (including modified versions) described in Embodiment 1. 【0079】 (Embodiment 3) Actuator 1B according to this embodiment differs from actuator 1 according to embodiment 1 in that it includes a driven cylinder 6, as shown in Figure 9. Hereinafter, components similar to those in embodiment 1 will be denoted by common reference numerals and their descriptions will be omitted as appropriate. 【0080】 The driven cylinder 6 is positioned outside the sector-shaped region R1 (see Figure 5). The driven cylinder 6 mechanically connects the fixed member 21 and the movable member 22. The driven cylinder 6 is configured to be extendable and retractable. In short, in the actuator 1B according to this embodiment, in addition to the support member 5 and the pair of drive units 3 and 4, the fixed member 21 and the movable member 22 are also connected by the driven cylinder 6. Therefore, it is possible to increase the load-bearing capacity (maximum tensile load) between the fixed member 21 and the movable member 22 compared to the case without the driven cylinder 6. Furthermore, improvements in drive stability and impact resistance can be expected compared to the case without the driven cylinder 6. 【0081】 Here, the driven cylinder 6 extends and retracts in conjunction with the extension and retraction of the pair of drive units 3 and 4. That is, unlike the pair of drive units 3 and 4 which extend and retract actively, the driven cylinder 6 itself does not extend or retract actively, but only extends and retracts passively in accordance with the extension and retraction of the pair of drive units 3 and 4. Therefore, no control is required for the driven cylinder 6, and simple control of the actuator 1B can be realized. 【0082】 More specifically, in a plan view, the driven cylinder 6, together with the pair of drive units 3 and 4, forms an equilateral triangle centered on the support member 5. In other words, in a plan view, the driven cylinder 6 and the pair of drive units 3 and 4 are arranged at 120-degree intervals in the circumferential direction of a virtual circle centered on the support member 5. 【0083】 The lower end of the driven cylinder 6, that is, the end on the side of the fixed member 21, is connected to the fixed member 21 by a third joint portion 61 with two or more degrees of freedom. In this embodiment, the third joint portion 61 is a three-degree-of-freedom magnetic ball joint that is magnetically connected using the magnetic force of a permanent magnet. 【0084】 Furthermore, the upper end of the driven cylinder 6, that is, the end on the movable member 22 side, is connected to the movable member 22 by a third joint portion 62 with two or more degrees of freedom. In this embodiment, the third joint portion 62 is a three-degree-of-freedom magnetic ball joint that is magnetically coupled using the magnetic force of a permanent magnet. 【0085】 Thus, the driven cylinder 6 has third joint portions 61 and 62 with two or more degrees of freedom at both ends in the longitudinal direction (vertical direction D3). Therefore, it is possible to provide the driven cylinder 6 while avoiding limitations on the range of motion of the movable member 22. 【0086】 However, in this embodiment, since the joint portions 31 and 41 on the fixed member 21 side of the pair of drive units 3 and 4 are joint portions with one degree of freedom, like a hinge structure, the movable member 22 is limited to two degrees of freedom: pitch movement around the first rotation axis Ax1 and roll movement around the second rotation axis Ax2. 【0087】 Furthermore, the third joint portions 61 and 62, which have two or more degrees of freedom, are not limited to magnetic ball joints, but may also be, for example, universal joints or spherical bearings. 【0088】 The configuration of Embodiment 3 (including modified versions) can be appropriately combined with various configurations (including modified versions) described in Embodiment 1 or Embodiment 2. 【0089】 (Embodiment 4) The actuator 1C according to this embodiment differs from the actuator 1B according to Embodiment 3 in that, as shown in Figure 10, the joint portions 31 and 41 at the lower ends of the pair of drive units 3 and 4, that is, the ends on the fixed member 21 side, are "second joint portions" with two or more degrees of freedom. Hereinafter, components similar to those in Embodiment 3 will be denoted by common reference numerals and their descriptions will be omitted as appropriate. 【0090】 In other words, each of the pair of drive units 3 and 4 has a second joint with two or more degrees of freedom at both ends in the longitudinal direction (vertical direction D3). In this embodiment, as an example, the joints 31 and 41 are magnetic ball joints that are magnetically coupled using the magnetic force of permanent magnets. As a result, there are no joints with only one degree of freedom in either the pair of drive units 3 and 4 or the driven cylinder 6. 【0091】 In the actuator 1C according to this embodiment, similar to embodiment 2, the movable member 22 is capable of rotational movement with "three degrees of freedom" around the pivot point P1. In other words, the pair of drive units 3 and 4 enable the movable member 22 to rotate around the first rotation axis Ax1 (pitch movement) and the second rotation axis Ax2 (roll movement), as well as to rotate around the third rotation axis Ax3 (yaw movement). 【0092】 Furthermore, the joint sections 31 and 32 with two or more degrees of freedom are not limited to magnetic ball joints, but may also be, for example, universal joints or spherical bearings. 【0093】 The configuration of Embodiment 4 (including modified versions) can be appropriately combined with the various configurations (including modified versions) described in Embodiment 1, Embodiment 2, or Embodiment 3. 【0094】 (Embodiment 5) The actuator 1D according to this embodiment differs from the actuator 1C according to Embodiment 4 in that, as shown in Figure 11, the lower end of the driven cylinder 6, that is, the end on the fixed member 21 side, is a joint portion 61 with one degree of freedom. Hereinafter, components similar to those in Embodiment 4 will be denoted by the same reference numerals and their descriptions will be omitted as appropriate. 【0095】 In this embodiment, as an example, the joint portion 61 of the driven cylinder 6 is a hinge structure. In this embodiment, since the joint portion 61 on the fixed member 21 side of the driven cylinder 6 is a single-degree-of-freedom joint portion like a hinge structure, the movable member 22 is limited to two degrees of freedom, pitch movement around the first rotation axis Ax1 and roll movement around the second rotation axis Ax2, similar to Embodiment 3. 【0096】 The configuration of Embodiment 5 (including modified versions) can be appropriately combined with the various configurations (including modified versions) described in Embodiment 1, Embodiment 2, Embodiment 3, or Embodiment 4. 【0097】 (summary) As described above, the actuator (1, 1A, 1B, 1C, 1D) according to the first embodiment comprises a fixed member (21), a movable member (22), a support member (5), and a pair of drive units (3, 4). The support member (5) mechanically connects the fixed member (21) and the movable member (22). The pair of drive units (3, 4) mechanically connect the fixed member (21) and the movable member (22) and are each extendable and retractable. The pair of drive units (3, 4) are located within a sector region (R1) with a vertex angle of less than 180 degrees, with the support member (5) as the vertex. The pair of drive units (3, 4) drive the movable member (22) with respect to the fixed member (21) with at least two degrees of freedom, with the support member (5) as the pivot point. 【0098】 According to this embodiment, a pair of drive units (3,4) located within a sector-shaped region (R1) with a vertex angle of less than 180 degrees, with the support member (5) as the apex, can drive the movable member (22) with at least two degrees of freedom relative to the fixed member (21), with the support member (5) as the pivot point. This makes it possible to achieve two degrees of freedom with a pair (two) drive units (3,4), which has the advantage of simplifying the structure and control compared to a configuration that requires three drive units. 【0099】 In the actuators (1, 1A, 1B, 1C, 1D) according to the second embodiment, the support member (5) has a first joint portion (51) with two or more degrees of freedom at at least one end in the longitudinal direction. 【0100】 In this embodiment, the movable member (22) is supported by the support member (5) relative to the fixed member (21) while enabling movement of two or more degrees of freedom. Therefore, it is possible to increase the load-bearing capacity (maximum tensile load) between the fixed member (21) and the movable member (22). 【0101】 In the actuators (1, 1A, 1B, 1C, 1D) according to the third embodiment, the first joint portion (51) is a magnetic ball joint, as in the second embodiment. 【0102】 According to this embodiment, the magnetic attractive force of the first joint portion (51) makes it possible to increase the load-bearing capacity (maximum tensile load) between the fixed member (21) and the movable member (22). Furthermore, compared to joints with two or more degrees of freedom other than magnetic ball joints, such as universal joints or spherical bearings, the structure of the first joint portion (51) can be simplified, and a wide range of motion (movable range) can be easily achieved. 【0103】 In the actuators (1, 1A, 1B, 1C, 1D) according to the fourth embodiment, in any of the first to third embodiments, each of the pair of drive units (3, 4) has a second joint unit (32, 42) with two or more degrees of freedom at at least one end in the longitudinal direction. 【0104】 In this embodiment, the movable member (22) is supported by a pair of drive units (3,4) relative to the fixed member (21) while enabling movement of two or more degrees of freedom. Therefore, it is possible to increase the load-bearing capacity (maximum tensile load) between the fixed member (21) and the movable member (22). 【0105】 In the fifth embodiment, the actuator (1, 1A, 1B, 1C, 1D) is located outside the sector-shaped region (R1) in any of the first to fourth embodiments, and mechanically connects a fixed member (21) and a movable member (22), further comprising an extendable driven cylinder (6). 【0106】 According to this embodiment, it is possible to increase the load-bearing capacity (maximum tensile load) between the fixed member (21) and the movable member (22) compared to the case without the driven cylinder (6). Furthermore, improvements in driving stability and impact resistance can be expected compared to the case without the driven cylinder (6). 【0107】 In the actuators (1, 1A, 1B, 1C, 1D) according to the sixth embodiment, the driven cylinder (6) has third joint portions (61, 62) with two or more degrees of freedom at both ends in the longitudinal direction, as in the fifth embodiment. 【0108】 According to this embodiment, it is possible to provide a driven cylinder (6) while avoiding limiting the range of motion (movable range) of the movable member (22). 【0109】 In the actuator (1, 1A, 1B, 1C, 1D) according to the seventh embodiment, in the fifth or sixth embodiment, the driven cylinder (6) extends and retracts in accordance with the extension and retraction of the pair of drive units (3, 4). 【0110】 According to this embodiment, control is unnecessary for the driven cylinder (6), and simple control of the actuators (1, 1A, 1B, 1C, 1D) can be achieved. 【0111】 In the actuator (1, 1A, 1B, 1C, 1D) according to the eighth embodiment, in any of the first to seventh embodiments, a pair of drive units (3, 4) drive a movable member (22) with three degrees of freedom relative to a fixed member (21), with the support member (5) as a fulcrum. 【0112】 According to this embodiment, the actuators (1, 1A, 1B, 1C, 1D) can achieve a wider variety of movements. 【0113】 The robot joint device (110) according to the ninth embodiment comprises an actuator (1, 1A, 1B, 1C, 1D) according to any of the first to eight embodiments, a first member (111) fixed to a fixed member (21), and a second member (112) fixed to a movable member (22). 【0114】 According to this embodiment, it is possible to realize two degrees of freedom with a pair (two) drive units (3,4), which has the advantage of simplifying the structure and control compared to a configuration that requires three drive units. 【0115】 The configurations relating to the second to eighth aspects are not essential to the actuators (1, 1A, 1B, 1C, 1D) and can be omitted as appropriate. [Explanation of symbols] 【0116】 Actuators 1, 1A, 1B, 1C, 1D 110 Robot joint devices 3,4 Drive unit 5. Support Member 6. Driven cylinder 21 Fixing member 22 Movable members 32,42 Second joint section 51. First joint section 61, 62 Third joint section 111 First Member 112 Second Member R1 sector area

Claims

[Claim 1] Fixing member and Movable member and A support member that mechanically connects the fixed member and the movable member, The fixed member and the movable member are mechanically connected and each comprises a pair of extendable and retractable drive units, The pair of drive units are Located within a sector-shaped region with a vertex angle of less than 180 degrees, with the aforementioned support member as its apex. The movable member is driven with respect to the fixed member by at least two degrees of freedom, with the support member acting as a fulcrum. Actuator. [Claim 2] The support member has a first joint portion with two or more degrees of freedom at at least one end in the longitudinal direction. The actuator according to claim 1. [Claim 3] The first joint is a magnetic ball joint. The actuator according to claim 2. [Claim 4] Each of the pair of drive units has a second joint portion with two or more degrees of freedom at at least one end in the longitudinal direction. The actuator according to any one of claims 1 to 3. [Claim 5] It is located outside the aforementioned sector-shaped region, mechanically connects the fixed member and the movable member, and further comprises an extendable driven cylinder. The actuator according to any one of claims 1 to 3. [Claim 6] The driven cylinder has a third joint portion with two or more degrees of freedom at both ends in the longitudinal direction. The actuator according to claim 5. [Claim 7] The driven cylinder extends and retracts in accordance with the extension and retraction of the pair of drive units. The actuator according to claim 5. [Claim 8] The pair of drive units drive the movable member with three degrees of freedom relative to the fixed member, with the support member as the pivot point. The actuator according to any one of claims 1 to 3. [Claim 9] An actuator according to any one of claims 1 to 3, A first member fixed to the aforementioned fixing member, The system comprises a second member fixed to the aforementioned movable member, Joint device for robots.

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