Parallel link mechanism

Abstract

To provide a parallel link mechanism that achieves both interference driving and gravitational separate speed reduction.SOLUTION: A parallel link mechanism 10A comprises: a first parallel link part 47 (40, 41 and 42) which has its base end part connected swingably to a second moving body 30; a second parallel link part 48 (42, 43 and 44) which has its base end part connected swingably to a tip part of the first parallel link part 47; a first arm part 45 which has its base end part connected rotatably to a first moving body 20 and has its tip part connected rotatably to an intermediate position of the second parallel link part 48; a second arm part 46a which has its base end part connected rotatably to the second moving body 30 and has its tip part connected rotatably to an intermediate position of th e first arm part 45; and linear motion units 60, 70 which can elevate and lower the moving bodies 20, 30 individually. The second parallel link part 48 has its tip part connected swingably to a hand device 50.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a parallel link mechanism that can be used as a working arm for performing various tasks. [Background technology]

[0002] One of the conventional link mechanisms that can be used as a working arm is a link mechanism 100 shown in Fig. 6 (see Patent Document 1). This link mechanism 100 was proposed by the present applicant and comprises moving bodies 110, 120, and 130 arranged on the same imaginary line extending in the direction of gravity, first arm sections 111, 111 having a first base end 111a rotatably connected to the moving body 110, second arm sections 121, 121 having a second base end 121a rotatably connected to the moving body 120, and a third base end 131a rotatably connected to the moving body 130. The workpiece also includes third arm sections 131, 131 whose third tip section 131b is rotatably connected to the second arm section 121 between the second base end section 121a and the second tip section 121b, a working device 140 rotatably connected to both the first tip section 111b and the second tip section 121b, and rotating machines 150, 151, 152 that can move the moving bodies 110, 120, 130 individually on the virtual straight line. Items marked with reference symbol W are work objects.

[0003] In this link mechanism 100, the sum of the forces generated by the three rotating machines 150, 151, and 152 becomes the force that lifts the work object W. In other words, in this link mechanism 100, the forces generated by the three rotating machines 150, 151, and 152 can be fully utilized to lift the work object W. On the other hand, in this link mechanism 100, it was not possible to adjust the reduction ratio in the horizontal direction (X direction) independently of the reduction ratio in the direction of gravity (Z direction).

[0004] In other words, this conventional link mechanism 100 was able to achieve "coupled drive" but not "gravitationally decoupled reduction (GDR)." Interference drive is explained in Non-Patent Document 1. Gravitationally decoupled actuation (GDR) is a concept similar to "gravitationally decoupled actuation (GDA)" explained in Non-Patent Document 1, and is defined for the first time by the present applicant in this specification. While GDA is a concept that refers to separating the drive actuators in the gravity direction and the non-gravity direction, GDR refers to separating the reduction ratios in the gravity direction and the non-gravity direction (they can be designed independently of each other). According to this definition, GDR is a necessary condition for GDA. Furthermore, while achieving GDA while using interference drive in the same gravity direction and non-gravity direction is, by definition, incompatible, achieving GDR while using interference drive in the same gravity direction and non-gravity direction is not necessarily incompatible by definition. In other words, interference drive and GDR can potentially be compatible. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-109253 [Non-patent literature]

[0006] [Non-Patent Document 1] Shigeo Hirose, "Miniaturization and Lightweighting of Robots", Journal of the Japan Society for Precision Engineering, 1994, Vol. 60, No. 7, pp. 913-919 Summary of the Invention [Problem to be solved by the invention]

[0007] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a parallel link mechanism that realizes both interference drive and gravity direction separated deceleration. [Means for solving the problem]

[0008] In order to solve the above problems, the parallel link mechanism according to the present invention includes a first moving body and a second moving body arranged on the same imaginary straight line, a first parallel link unit having a first base end and a first tip end, with the first base end swingably connected to the second moving body, a second parallel link unit having a second base end and a second tip end, with the second base end swingably connected to the first parallel link unit at the first tip end, and a third parallel link unit having a third base end and a third tip end, with the third base end rotatably connected to the first moving body and the third tip end swingably connected to the second base end and the second tip end. a first arm section rotatably connected to the second parallel link section at a first intermediate position between the first and second base ends, a second arm section having a fourth base end and a fourth tip end, the fourth base end being rotatably connected to the second moving body and the fourth tip end being rotatably connected to the first arm section at a second intermediate position between the third base end and the third tip end, and linear motion means capable of moving the first moving body and the second moving body individually on the virtual straight line, wherein the second parallel link section is swingably connected to the end device at the second tip end.

[0009] The parallel link mechanism can be configured, for example, such that the linear motion means includes a first ball screw shaft and a second ball screw shaft parallel to the virtual straight line, and a first rotating machine and a second rotating machine connected one-to-one to the first ball screw shaft and the second ball screw shaft, and the first ball screw shaft is threaded onto the first moving body but not threaded onto the second moving body, and the second ball screw shaft is threaded onto the second moving body but not threaded onto the first moving body.

[0010] The parallel link mechanism may further include a base portion placed on a floor surface, and a support portion extending vertically upward from the base portion and including the linear motion means.

[0011] Preferably, the base of the parallel link mechanism includes a third rotating machine connected to the support column.

[0012] It is preferable that the parallel link mechanism further includes a first constant force spring that applies a constant vertical upward force to the first moving body regardless of the displacement of the first moving body, and a second constant force spring that applies a constant vertical upward force to the second moving body regardless of the displacement of the second moving body.

[0013] In the parallel link mechanism, the first parallel link section includes a first link member having one end rotatably connected to the second moving body, a second link member having one end rotatably connected to the second moving body, and a third link member connected to the other end of the first link member and the other end of the second link member, and the second parallel link section includes a fourth link member having one end rotatably connected to the other end of the first link member and the other end rotatably connected to the end device, and a fifth link member having one end rotatably connected to the other end of the second link member and the other end rotatably connected to the end device. It is preferable that the actuator includes a member, wherein the first link member, the second link member and the first arm portion are parallel to each other, the fourth link member, the fifth link member and the second arm portion are parallel to each other, the third link member, a line connecting the two rotation axes on the second movable body and a line connecting the two rotation axes on the end device are parallel to each other, the distance between the fourth base end and the fourth tip end is equal to the distance between the third base end and the second intermediate position, and the connection point of the fifth link member and the end device and the second intermediate position are in the same plane perpendicular to the above-mentioned imaginary line. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a parallel link mechanism that realizes both interference drive and gravity direction separated deceleration. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a perspective view showing a parallel link mechanism according to a first embodiment of the present invention. [Figure 2] 3A to 3C are schematic side views illustrating the operation of moving the end device in the Z direction of the parallel link mechanism according to the first embodiment of the present invention. [Figure 3]3A to 3C are schematic side views illustrating the operation of moving the end device in the X direction of the parallel link mechanism according to the first embodiment of the present invention. [Figure 4] FIG. 1A is a schematic side view showing a parallel link mechanism according to a second embodiment of the present invention, FIG. 1B is a schematic side view showing a parallel link mechanism according to a first embodiment of the present invention, and FIG. 1C is a schematic side view showing a parallel link mechanism according to a third embodiment of the present invention. [Figure 5] FIG. 10 is a schematic side view showing the operation of moving the end device in the X direction of the parallel link mechanism according to the fourth embodiment of the present invention. [Figure 6] FIG. 10 is a perspective view showing a conventional link mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the parallel link mechanism according to the present invention will be described with reference to the accompanying drawings. Although the following describes the case where the parallel link mechanism is used as a working arm, the parallel link mechanism according to the present invention can also be used as part of other robots.

[0017] [First Example] 1 shows a parallel link mechanism 10A according to a first embodiment of the present invention. The parallel link mechanism 10A can move any hand device 50 to any position in XYZ space within its movable range, and as shown in the figure, includes a base 90 placed on the floor, a support 80, two movable bodies 20 and 30, and seven link members 40, 41, 42, 43, 44, 45, and 46a. In this embodiment, the floor is parallel to the horizontal XY plane, and the Z direction, which is perpendicular to the X and Y directions, is the direction of gravity (vertical direction).

[0018] The support column 80 extends in the +Z direction from the base 90. The support column 80 includes a bottom 81, a ceiling 82 spaced apart from the bottom 81 in the +Z direction, a rear wall 83 and side walls 84, 85 connecting the bottom 81 and the ceiling 82, a first linear motion unit 60, and a second linear motion unit 70. The two side walls 84, 85 are spaced apart in the Y direction so as to sandwich the linear motion units 60, 70 therebetween. The linear motion units 60, 70 are also spaced apart from each other in the Y direction.

[0019] The support column 80 is connected to the base 90 at the bottom 81 so as to be rotatable around the Z axis. In the following description, when the support column 80 rotates relative to the base 90, the orientations of the X and Y axes change accordingly. In other words, the link mechanism consisting of the seven link members 40, 41, 42, 43, 44, 45, and 46a always extends from the support column 80 in the +X direction.

[0020] The first linear motion unit 60 includes a first ball screw shaft 61 extending in the Z direction, a first reducer 62 connected to the lower end of the first ball screw shaft 61, and a first rotating machine 63 having an output shaft connected to the first reducer 62. In other words, the output shaft of the first rotating machine 63 is connected to the first ball screw shaft 61 via the first reducer 62. Therefore, when the output shaft of the first rotating machine 63 rotates, the first ball screw shaft 61 also rotates in a direction corresponding to the direction of the rotation. At this time, the rotation speeds of the first ball screw shaft 61 and the output shaft of the first rotating machine 63 may be the same or different.

[0021] The second linear motion unit 70 has a configuration similar to that of the first linear motion unit 60. That is, the second linear motion unit 70 includes a second ball screw shaft 71 extending in the Z direction, a second reducer 72 connected to the lower end of the second ball screw shaft 71, and a second rotating machine 73 having an output shaft connected to the second reducer 72. That is, the output shaft of the second rotating machine 73 is connected to the second ball screw shaft 71 via the second reducer 72. Therefore, when the output shaft of the second rotating machine 73 rotates, the second ball screw shaft 71 also rotates in a direction corresponding to the direction of the rotation. At this time, the rotation speeds of the second ball screw shaft 71 and the output shaft of the second rotating machine 73 may be the same or different.

[0022] The first moving body 20 is threadedly engaged with the first ball screw shaft 61 of the first linear motion unit 60. Therefore, when the first ball screw shaft 61 rotates, the first moving body 20 moves in a direction corresponding to the direction of rotation (+Z direction / -Z direction) at a speed corresponding to the number of rotations. On the other hand, the first moving body 20 is not threadedly engaged with the second ball screw shaft 71 of the second linear motion unit 70. Therefore, the rotation of the second ball screw shaft 71 does not affect the first moving body 20.

[0023] The second moving body 30 is threadedly engaged with the second ball screw shaft 71 of the second linear motion unit 70 above the first moving body 20. Therefore, when the second ball screw shaft 71 rotates, the second moving body 30 moves in a direction corresponding to the direction of rotation (+Z direction / -Z direction) at a speed corresponding to the number of rotations. On the other hand, the second moving body 30 is not threadedly engaged with the first ball screw shaft 61 of the first linear motion unit 60. Therefore, the rotation of the first ball screw shaft 61 does not affect the second moving body 30.

[0024] It can be said that the moving bodies 20 and 30 are arranged on the same imaginary straight line, and that the ball screw shafts 61 and 71 are parallel to this imaginary straight line.

[0025] The first link member 40 has a base end (= the end on the support part 80 side; the same applies below) and a tip end (= the end on the end device 50 side; the same applies below). The base end of the first link member 40 is connected to the second movable body 30 so as to be rotatable around the Y axis.

[0026] The second link member 41 has a base end and a tip end. The base end of the second link member 41 is connected to the second moving body 30 so as to be rotatable about the Y axis at a predetermined distance below the connection point between the second moving body 30 and the first link member 40. The length of the second link member 41 is equal to the length of the first link member 40.

[0027] The third link member 42 has an upper end and a lower end. The upper end of the third link member 42 is connected to the tip of the first link member 40 so as to be rotatable about the Y axis. The lower end of the third link member 42 is connected to the tip of the second link member 41 so as to be rotatable about the Y axis. The distance between the connection point of the first link member 40 and the third link member 42 and the connection point of the second link member 41 and the third link member 42 is equal to the distance between the connection point of the first link member 40 and the second movable body 30 and the connection point of the second link member 41 and the second movable body 30 (hereinafter referred to as distance Z1).

[0028] The fourth link member 43 has a base end and a tip end. The base end of the fourth link member 43 is connected to both the tip end of the first link member 40 and the upper end of the third link member 42 so as to be rotatable about the Y axis. In addition, the tip end of the fourth link member 43 is connected to the end device 50 so as to be rotatable about the Y axis.

[0029] The fifth link member 44 has a base end and a tip end. The base end of the fifth link member 44 is connected to both the tip end of the second link member 41 and the lower end of the third link member 42 so as to be rotatable about the Y axis. The tip end of the fifth link member 44 is connected to the end device 50 so as to be rotatable about the Y axis, a distance Z1 below the connection point between the fourth link member 43 and the end device 50. The length of the fifth link member 44 is equal to the length of the fourth link member 43.

[0030] The first link member 40, the second link member 41, and the third link member 42 correspond to the "first parallel link unit" 47 of the present invention. The first parallel link unit 47 has a base end and a tip end, and can be said to be connected to the second moving body 30 at the base end so as to be able to swing freely.

[0031] The third link member 42, the fourth link member 43, and the fifth link member 44 correspond to the "second parallel link unit" 48 of the present invention. The second parallel link unit 48 has a base end and a tip end, and can be said to be swingably connected to the tip end of the first parallel link unit 47 at the base end and swingably connected to the end device 50 at the tip end.

[0032] The sixth link member 45 has a base end and a tip end. The base end of the sixth link member 45 is connected to the first movable body 20 so as to be rotatable about the Y axis. In addition, the tip end of the sixth link member 45 is connected to the fifth link member 44 at a first intermediate position 44a (see FIG. 2, etc.) so as to be rotatable about the Y axis. In other words, the tip end of the sixth link member 45 is connected to the intermediate position of the second parallel link unit 48 so as to be rotatable.

[0033] The seventh link member 46a has a base end and a tip end. The base end of the seventh link member 46a is connected to both the base ends of the second movable body 30 and the second link member 41 so as to be rotatable about the Y axis. In addition, the tip end of the seventh link member 46a is connected to the sixth link member 45 at a second intermediate position 45a (see FIG. 2, etc.) so as to be rotatable about the Y axis.

[0034] In this embodiment, the first link member 40, the second link member 41 and the sixth link member 45 are parallel to each other, the fourth link member 43, the fifth link member 44 and the seventh link member 46a are parallel to each other, the third link member 42, the line connecting the two rotation axes on the second moving body 30 and the line connecting the two rotation axes on the hand device 50 are parallel to each other, the distance between the connection point of the seventh link member 46a and the second moving body 30 and the second intermediate position 45a is equal to the distance between the connection point of the sixth link member 45 and the first moving body 20 and the second intermediate position 45a (i.e., these two connection points and the second intermediate position 45a form an isosceles triangle), and further the Z-direction position (height) of the connection point of the fifth link member 44 and the hand device 50 is the same as the Z-direction position (height) of the second intermediate position 45a. It can also be said that the connection point between the fifth link member 44 and the end device 50 and the second intermediate position 45a are located within the same plane (XY plane) perpendicular to the Z direction.

[0035] The sixth link member 45 corresponds to the "first arm portion" of the present invention, and the seventh link member 46a corresponds to the "second arm portion" of the present invention.

[0036] Next, the relationship between the moving speed of the moving bodies 20 and 30 caused by the linear motion units 60 and 70 and the moving speed of the end device 50 will be considered.

[0037] In the parallel link mechanism 10A according to this embodiment, the above relationship can be simply expressed as the following equation.

number

[0038] Equation (1) expresses the difference in the moving speeds of the first moving body 20 and the second moving body 30 (=dot d1-dot d2), which determines the moving speed v of the end device 50 in the X direction. x is determined, and the moving speed v of the hand device 50 in the Z direction is determined by the sum of the moving speeds of the first moving body 20 and the second moving body 30 (=dot d1+dot d2). z In other words, the parallel link mechanism 10A according to this embodiment is a so-called differential mechanism.

[0039] Coefficient J, which is the reduction ratio in the X direction x can be expressed as a function of the distance (=d1-d2) between the first moving body 20 and the second moving body 30, as in the following equation.

number

[0040] On the other hand, in the configuration shown in Figure 1, the coefficient J z In other words, in this embodiment, the average speed of the moving bodies 20 and 30 is 1 / 2 (constant). z This becomes:

[0041] In this way, according to the parallel link mechanism 10A of this embodiment, the coefficient J z Independently of this, the coefficient J, which is the deceleration ratio in the X direction, which is the non-gravitational direction, x In other words, the parallel link mechanism 10A according to this embodiment can achieve gravity direction deceleration (GDR).

[0042] Next, the relationship between the driving force of the linear motion units 60 and 70 and the translational force of the end device 50 will be considered.

[0043] In the parallel link mechanism 10A according to this embodiment, the above relationship can be expressed as follows from the relationship of equation (1) using the principle of virtual work:

number

number

[0044] Equation (4) expresses the translational force f of the end device 50 in the X direction due to the difference in the driving forces of the first linear motion unit 60 and the second linear motion unit 70 (= f1 - f2). x is determined, and the sum of the driving forces of the first linear motion unit 60 and the second linear motion unit 70 (= f1 + f2) determines the translational force f of the end device 50 in the Z direction. z This shows that the following can be determined.

[0045] As mentioned above, in the configuration shown in Figure 1, the coefficient J, which is the reduction ratio in the Z direction, z is 1 / 2 (constant). Therefore, the following equation is obtained from equation (4):

number

[0046] Equation (5) shows that the sum of the driving forces f1 and f2 of the two linear motion units 60 and 70 is the translational force f in the Z direction of the end device 50. zIn other words, this equation indicates that interference drive is achieved by the parallel link mechanism 10A according to this embodiment.

[0047] Next, the operation of the parallel link mechanism 10A according to this embodiment will be described.

[0048] 2, when the first linear motion unit 60 and the second linear motion unit 70 are operated to move (raise) the first moving body 20 and the second moving body 30 in the +Z direction by the same amount, the end device 50 also rises by the same amount (see (A) → (B) → (C) in the same figure). Conversely, when the first linear motion unit 60 and the second linear motion unit 70 are operated to move (lower) the first moving body 20 and the second moving body 30 in the -Z direction by the same amount, the end device 50 also descends by the same amount (see (C) → (B) → (A) in the same figure). In either case, the end device 50 does not move at all in the X direction.

[0049] As shown in Figure 3, when the second linear motion unit 70 is operated to lower the second moving body 30 while the first linear motion unit 60 is operated to raise the first moving body 20 by the same amount, the end device 50 moves in the +X direction (moves away) (see (A) → (B) → (C) in the same figure). Conversely, when the second linear motion unit 70 is operated to raise the second moving body 30 while the first linear motion unit 60 is operated to lower the first moving body 20 by the same amount, the end device 50 moves in the -X direction (moves closer) (see (C) → (B) → (A) in the same figure). In either case, the end device 50 does not move at all in the Z direction.

[0050] Of course, when moving the endoscope device 50 in the X direction, it is not necessary to move the first moving body 20 and the second moving body 30 by the same amount in opposite directions. For example, the endoscope device 50 may be moved away by raising the first moving body 20 while keeping the second moving body 30 fixed. In this case, the endoscope device 50 also moves in the +Z direction. Alternatively, the endoscope device 50 may be moved closer by lowering the first moving body 20 while keeping the second moving body 30 fixed. In this case, the endoscope device 50 also moves in the -Z direction.

[0051] As described above, the parallel link mechanism 10A according to the first embodiment can simultaneously achieve both gravity-direction deceleration (GDR) and interference drive in the same gravity direction (Z direction) and non-gravity direction (X direction). In addition, the parallel link mechanism 10A has the following advantages: (1) the adoption of a pantograph structure makes it possible to ensure a wider range of motion (particularly the range of motion in the X direction) of the end device 50 than in the conventional mechanism 100; and (2) the adoption of a parallel link structure makes the mechanism more resistant to external forces overall than the conventional mechanism 100.

[0052] [Second Example] As shown in FIG. 4(A), a parallel link mechanism 10B according to a second embodiment of the present invention differs from the parallel link mechanism 10A (see FIG. 4(B)) in that it has a shorter seventh link member 46b instead of the seventh link member 46a, that the sixth link member 45 is connected to the fifth link member 44 at a position (first intermediate position 44b) closer to the base end than the first intermediate position 44a, and that the seventh link member 46b is connected to the sixth link member 45 at a position (second intermediate position 45b) closer to the base end than the second intermediate position 45a.

[0053] According to this configuration, the reduction ratio in the X direction becomes smaller, and the end device 50 can be moved in the X direction at a higher speed. On the other hand, the translational force of the end device 50 in the X direction decreases.

[0054] [Third Example] As shown in FIG. 4(C), a parallel link mechanism 10C according to a third embodiment of the present invention differs from the parallel link mechanism 10A (see FIG. 4(B)) in that it has a longer seventh link member 46c instead of the seventh link member 46a, that the sixth link member 45 is connected to the fifth link member 44 at a position (first intermediate position 44c) closer to the tip end than the first intermediate position 44a, and that the seventh link member 46c is connected to the sixth link member 45 at a position (second intermediate position 45c) closer to the tip end than the second intermediate position 45a.

[0055] According to this configuration, the reduction ratio in the X direction increases, and it is possible to increase the translational force in the X direction of the end device 50. On the other hand, the moving speed of the end device 50 in the X direction decreases.

[0056] [Fourth Example] 5, a parallel link mechanism 10D according to a fourth embodiment of the present invention has a configuration in which the upper limit of the parallel link mechanism 10A according to the first embodiment is inverted. With this configuration, the same effects as those of the first embodiment can be obtained.

[0057] [Variations] Although the first to fourth embodiments of the parallel link mechanism according to the present invention have been described above, the configuration of the present invention is not limited to these.

[0058] For example, the parallel link mechanism according to the present invention may further include gravity compensation means. 2 ], then the gravity acting on the payload is f x =0, f z =-mg, and by substituting these into equation (3), the following equation is obtained.

number

[0059] In addition, if the distance between the connection point of the seventh link member 46a (46b, 46c) and the second moving body 30 and the second intermediate position 45a (45b, 45c) is not equal to the distance between the connection point of the sixth link member 45 and the first moving body 20 and the second intermediate position 45a (45b, 45c), the coefficient J z becomes a value different from 1 / 2, the force to be applied to the first linear motion unit 60 (first moving body 20) and the force to be applied to the second linear motion unit 70 (second moving body 30) are no longer 1:1.

[0060] The base 90 may further include a third rotating machine (not shown in FIG. 1) whose output shaft is connected to the bottom 81 of the support column 80. This configuration enables the support column 80 to rotate around the Z axis, thereby expanding the range of motion of the end device 50.

[0061] In the first to fourth embodiments, the X and Y directions are horizontal directions and the Z direction is the direction of gravity, but this is not limitative, and for example, the X or Y direction may be the direction of gravity.

[0062] Up to this point, the linear motion means has been described as being composed of a first ball screw shaft and a second ball screw shaft parallel to an imaginary line, but it is not limited to ball screws and may be composed of other linear motion means such as slide screws, racks and pinions, liner units, or linear shaft motors. If a slide screw with high friction and poor transmission efficiency is chosen instead of a ball screw with low friction and good transmission efficiency, the linear motion actuator will have a so-called self-locking function, and will not reverse drive unless a driving force is actively applied. However, since a self-locking function is often advantageous when transporting heavy objects, a slide screw can also be selected in that case.

[0063] A similar locking function can also be achieved by using a linear motion means such as a ball screw and a motor that rotates the linear motion means such as a ball screw, and attaching an (electromagnetic) brake or the like to the motor. In this case, it is necessary to attach an extra brake or the like, but it is possible to obtain a locking function for the output shaft while using, for example, a ball screw with good transmission efficiency. [Explanation of symbols]

[0064] 10A, 10B, 10C, 10D Parallel link mechanism 20 First Mobile Unit 30 Second Mobile Unit 40 first link member 41 second link member 42 Third link member 43 Fourth link member 44 Fifth link member 44a,44b,44c 1st intermediate position 45 Sixth link member (first arm portion) 45a,45b,45c 2nd intermediate position 46a, 46b, 46c Seventh link member (second arm portion) 47 First parallel link section 48 Second parallel link section 50 Hand Device 60 First linear unit 61 First ball screw shaft 62 1st reducer 63 First Rotating Machine 70 Second linear unit 71 Second ball screw shaft 72 2nd reducer 73 Second Rotating Machine 80 Support section 81 Bottom 82 Ceiling 83 Back wall 84 Side wall 85 Side wall 90 Base

Claims

1. a first moving body and a second moving body arranged on the same virtual straight line; a first parallel link unit having a first base end portion and a first tip end portion, the first base end portion being swingably connected to the second moving body; a second parallel link unit having a second base end portion and a second tip end portion, the second base end portion being swingably connected to the first parallel link unit at the first tip end portion; a first arm portion having a third base end portion and a third tip end portion, the third base end portion being rotatably connected to the first movable body, and the third tip end portion being rotatably connected to the second parallel link portion at a first intermediate position between the second base end portion and the second tip end; a second arm portion having a fourth base end portion and a fourth tip end portion, the fourth base end portion being rotatably connected to the second movable body, and the fourth tip end portion being rotatably connected to the first arm portion at a second intermediate position between the third base end portion and the third tip end; a linear motion means for moving the first moving body and the second moving body individually on the virtual straight line; Equipped with the first parallel link unit includes a first link member having one end rotatably connected to the second moving body, a second link member having one end rotatably connected to the second moving body, and a third link member connected to the other end of the first link member and the other end of the second link member, the second parallel link unit includes a fourth link member having one end rotatably connected to the other end of the first link member and the other end rotatably connected to a hand device, and a fifth link member having one end rotatably connected to the other end of the second link member and the other end rotatably connected to the hand device, the first link member, the second link member, and the first arm portion are parallel to one another, the fourth link member, the fifth link member, and the second arm portion are parallel to each other, a line connecting the two rotation axes on the third link member and the second movable body and a line connecting the two rotation axes on the end device are parallel to each other; a distance between the fourth base end portion and the fourth tip end portion is equal to a distance between the third base end portion and the second intermediate position; The connection point of the fifth link member and the end device and the second intermediate position are in the same plane perpendicular to the virtual straight line. A parallel link mechanism characterized by:

2. The linear motion means is a first ball screw shaft and a second ball screw shaft parallel to the imaginary line; a first rotating machine and a second rotating machine connected to the first ball screw shaft and the second ball screw shaft in a one-to-one relationship; Including, the first ball screw shaft is threadedly engaged with the first movable body and is not threadedly engaged with the second movable body; The second ball screw shaft is screwed into the second movable body and is not screwed into the first movable body.

2. The parallel link mechanism according to claim 1.

3. a base that is installed on the floor; a support portion extending vertically upward from the base portion and including the linear motion means; 3. The parallel link mechanism according to claim 2, further comprising:

4. The base includes a third rotating machine coupled to the support column.

4. The parallel link mechanism according to claim 3.

5. a first constant force spring that applies a constant vertical upward force to the first moving body regardless of displacement of the first moving body; a second constant force spring that applies a constant vertical upward force to the second moving body regardless of the displacement of the second moving body; 5. The parallel link mechanism according to claim 3, further comprising:

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