Multi-joint robot

Abstract

A multi-joint robot (1) includes a base (2), an arm (3) supported so as to be able to rotate relative to the base (2) about a prescribed axis (A) within a rotation angle range of less than ±180°, and a hollow support column (6) erected from the base (2) in parallel with the axis (A) outside the rotation angle range of the arm (3), a wire member (20) being routed from the base (2) to the arm (3) via the inside of the support column (6). The multi-joint robot (1) includes a stopper (16) embedded in a side surface of the support column (6) so as to abut against a side surface of the arm (3) rotated beyond the rotation angle range.

Description

Technical Field

[0001] This disclosure relates to a multi-joint robot. Background Technology

[0002] Previously, a SCARA robot was known to have a hollow support behind a base set on the ground, and cables were routed through the inside of the support on an arm that was supported so that it could rotate relative to the base about a vertical axis (see, for example, Patent Document 1 and Patent Document 2).

[0003] In these SCARA robots, the limiter consists of a bolt head and a rubber elastic part. The limiter is used to limit the rotation angle of the arm, wherein the bolt head is fastened to the lower surface of the arm and the elastic part is fixed to the side of the base.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-140456

[0007] Patent Document 2: Japanese Patent Application Publication No. 2015-85393 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] When handling heavy SCARA robots, limiters using bolt heads cannot adequately absorb kinetic energy. Furthermore, the limited space available for large limiters capable of absorbing significant kinetic energy can sometimes further restrict the arm's rotation angle range.

[0010] Therefore, there is a need for a multi-joint robot that can absorb a large amount of kinetic energy while ensuring a wider range of arm rotation angles.

[0011] Solution for solving the problem

[0012] One aspect of this disclosure is a multi-joint robot comprising: a base; an arm supported for rotation about a predetermined axis within a rotation angle range of less than ±180° relative to the base; and a hollow support column erected parallel to the axis from the base outside the rotation angle range of the arm, with linear bodies routed from the base to the arm via the interior of the support column. The multi-joint robot includes a limiter embedded in the side of the support column, abutting against the side of the arm rotating beyond the rotation angle range. Attached Figure Description

[0013] Figure 1This is a side view showing a robot according to one embodiment of the present disclosure.

[0014] Figure 2 It is shown Figure 1 A top view showing the relationship between the rotation angle range of the robot's first arm and the position of the support pillar used for wiring.

[0015] Figure 3 This is to explain to Figure 1 A partial longitudinal section view of the lines installed inside the robot's support.

[0016] Figure 4 It shows that Figure 3 A partial longitudinal section view of the line body fixed inside the support column.

[0017] Figure 5 This is an explanation Figure 1 A partial 3D view of the robot's support column and the limiters assembled on the support column.

[0018] Figure 6 It is shown Figure 1 The longitudinal section view of the robot's support column, the limiter assembled in the recess, and the gasket.

[0019] Figure 7 It is an explanation and Figure 1 The relationship between the robot's limiters, a side view of the limiters, and a partial cross-sectional view of the first arm.

[0020] Figure 8 It is shown Figure 1 A three-dimensional diagram of a modified example of a robot's limiter.

[0021] Figure 9 This is an explanation Figure 8 The relationship between the limiter and the first arm, a side view of the limiter, and a partial cross-sectional view of the first arm. Detailed Implementation

[0022] The robot 1 according to one embodiment of the present disclosure will now be described with reference to the accompanying drawings.

[0023] like Figure 1 As shown, the robot 1 according to this embodiment is, for example, a SCARA robot. Furthermore, the structure disclosed herein is not limited to SCARA robots and can be applied to other multi-joint robots with any axis structure.

[0024] The robot 1 of this embodiment includes a base 2, a first arm (arm) 3, and a second arm 4. The base 2 is disposed on the ground. The first arm 3 is supported so as to be able to rotate relative to the base 2 about a vertical first axis A. The second arm 4 is supported so as to be able to rotate about a second axis B parallel to the first axis A. A ball screw spline shaft 5 is provided at the front end of the second arm 4. The ball screw spline shaft 5 is driven to move up and down in the direction along a vertical third axis C and to rotate about the third axis C.

[0025] The first arm 3 is mounted on the upper surface of the base 2. For example... Figure 2 As shown by the solid line, the first arm 3 is supported so that it can rotate relative to the base 2 from the origin position extending forward, about the first axis A within a rotation angle range of less than ±180°, for example, ±140°.

[0026] On base 2, at a position away from the rear of the first arm 3, i.e. Figure 2 Outside the rotation angle range of the first arm 3, as indicated by the dashed line, a support column 6 is provided, which rises vertically from the upper surface of the base 2 along the first axis A.

[0027] The support column 6 is integrally mounted on the base 2, and a connecting part 7 is provided on the upper part of the support column 6 between the support column 6 and the first arm 3.

[0028] The base 2, the support column 6, the connecting part 7, and the first arm 3 have hollow structures. In addition, a hollow hole 8 is provided on the upper surface of the first arm 3 near the first axis A, which connects the internal space of the connecting part 7 and the internal space of the first arm 3.

[0029] The connecting part 7 includes a connecting member 9 and a cover member 10. The connecting member 9 connects the upper part of the support column 6 and the upper surface of the first arm 3. The cover member 10 is detachably mounted on the upper part of the connecting member 9 using bolts. By removing the cover member 10 from the connecting member 9, the internal space of the support column 6 and the hollow hole 8 of the first arm 3 are exposed upwards, thereby facilitating the setting of the line body 20, which will be described later.

[0030] The wire body 20 is introduced into the first arm 3 through the hollow hole 8 from the wiring board provided on the back of the base 2, through the interior of the base 2, the interior of the support 6, and the interior of the connecting part 7. The wire body 20 includes cables for driving the second arm 4 and the ball screw spline shaft 5, as well as cables or air pipes for driving tools mounted on the ball screw spline shaft 5.

[0031] To install the line body 20 on the robot 1, firstly, with the cover member 10 removed from the connecting member 9, the internal space of the support column 6 and the hollow hole 8 of the first arm 3 are exposed. In this state, the line body 20 is pulled out from the base 2 side through the internal space of the support column 6, as shown... Figure 3 As shown, the linear body 20 is secured to the L-shaped mounting fitting 11 using a binding device 12 such as nylon straps. Then, the secured linear body 20 and mounting fitting 11 are returned together to the interior space of the support column 6, as shown. Figure 4 As shown, the mounting accessory 11 is fixed to the connecting member 9.

[0032] Therefore, the line body 20 can be easily fixed to the robot 1. Furthermore, the front end portion of the line body 20 can be easily inserted into the first arm 3 through the hollow hole 8 of the exposed first arm 3 and connected to the motor 13 or the like of the second arm 4, which is located further forward, making setup easier.

[0033] The motor 14 and reducer 15 that drive the first arm 3 relative to the base 2 are disposed in the base 2 and are fixed to the first arm 3 and the base 2 from below on the first axis A.

[0034] According to the robot 1 of this embodiment, such as Figure 5 As shown, a limiter 16 is provided on the side of the support column 6. The support column 6 is cylindrical, and has recesses 6a on both sides of the first axis A in the circumferential direction, with a portion of the outer circumferential surface cut off. The bottom surface of each recess 6a is formed by a plane that is approximately parallel to the first axis A. An opening 17 and a plurality of screw holes 18 are provided on the bottom surface of each recess 6a. The opening 17 communicates with the internal space of the support column 6, and the plurality of screw holes 18 are formed around the opening 17.

[0035] Each limiter 16 has a shape complementary to each recess 6a, filling each recess 6a when embedded in it, and has an outer surface formed by an arcuate surface that is part of the cylindrical surface of the outer periphery of the support column 6. It is made of a metal material with a wall thickness thinner than that of the support column 6. Each limiter 16 closes the opening 17 of each recess 6a by being embedded in it, and is detachably mounted on the support column 6 by means of a plurality of bolts 19 fastened in screw holes 18.

[0036] like Figure 5 as well as Figure 6 As shown, a gasket (sealing member) 21 is sandwiched between the bottom surface of each limiter 16 and each recess 6a. With the gasket 21 sandwiched, by fixing each limiter 16 to each recess 6a, the opening 17 of each recess 6a is sealed, which can prevent liquid or dust from entering the support column 6 from the outside.

[0037] Each limiter 16 is embedded in the recess 6a of the support column 6 at the center position along the first axis A, which is the same as the center position of the side of the first arm 3 along the first axis A.

[0038] like Figure 7 As shown in the cross-section, the two sides of the first arm 3 have a convex shape along its entire length in the longitudinal direction of the first arm 3, with a ridge 22 protruding outward from the center in the direction along the first axis A. The convex shape is formed, for example, by two planes intersecting at an angle of 174°-176°.

[0039] The protruding shapes on the two sides of the first arm 3 are formed by the draft angle when the first arm 3 is constructed from a casting.

[0040] The function of the robot 1 configured as described in this embodiment will be explained below.

[0041] According to the robot 1 of this embodiment, such as Figure 2 As shown, under normal working conditions, the first arm 3 operates within a rotation angle range of ±140°, and the side of the first arm 3 will not contact the limiter 16 of the support column 6.

[0042] However, if calibration is lost for some reason, the first arm 3 will operate beyond the normal rotation angle range, resulting in one side of the first arm 3 coming into contact with the limiter 16 embedded in the support column 6.

[0043] In this situation, the convex side of the first arm 3 contacts and deforms the limiter 16 at the position of the most prominent ridge 22. Furthermore, during the period until the first arm 3 stops, the side of the first arm 3 gradually embeds into the outer surface of the limiter 16.

[0044] In other words, the kinetic energy of the first arm 3 is absorbed by deforming the limiter 16. In this case, according to this embodiment, the side of the first arm 3 is in contact with the outer surface of the limiter 16 over a wide range before the first arm 3 stops. Therefore, it has the advantage of being able to fully absorb the kinetic energy of the first arm 3 and stop it more reliably, even when the robot 1 has a large transportable weight or a high operating speed.

[0045] Furthermore, according to the robot 1 of this embodiment, since the limiter 16 is assembled on the support column 6 for the wiring line body 20, it is not necessary to provide space for setting the limiter 16 on the outside of the support column 6, and the limitation on the rotation angle range of the first arm 3 can be minimized.

[0046] Furthermore, since the limiter 16 is detachably mounted on the recess 6a of the support column 6 using bolts 19, the deformed limiter 16 can be easily replaced.

[0047] Furthermore, by removing the limiter 16 from the recess 6a of the support column 6, the opening 17 provided on the bottom surface of the recess 6a can be opened. This has the advantage that the line body 20 can be easily removed from the base 2 through the internal space of the support column 6 and the wiring of the line body 20 can be easily performed using the opened opening 17.

[0048] Furthermore, the robot 1 according to this embodiment has the following advantages: by embedding the limiter 16 into the recess 6a of the support column 6 to form a single cylindrical surface that smoothly connects the outer peripheral surface of the support column 6 and the outer surface of the limiter 16, a step portion for accumulating liquid or dust is not formed at the upper part of the limiter 16. This reduces the occurrence of problems such as liquid or dust accumulating at the step portion adhering to the workpiece being processed. This is especially effective when the workpiece is food.

[0049] Furthermore, in this embodiment, since the wiring line 20 is routed from the upper surface of the first arm 3 to the inside of the first arm 3 via the erected support column 6 behind the first arm 3, it is not necessary to make the reducer 15 and the like below the first arm 3 into a hollow structure. This prevents the base 2 from becoming too large and increasing costs.

[0050] Furthermore, in this embodiment, the outer peripheral surface of the limiter 16 is formed into a flat shape by utilizing the convex shape of the side surface created by the draft angle when the first arm 3 is formed from the casting. Alternatively, as... Figure 8 and Figure 9 As shown, the side of the first arm 3 can also be flat, and the outer surface of the limiter 16 can be a protruding shape that protrudes outward from the center.

[0051] In this case, such as Figure 8 As shown, it is preferable to form the upper edge of the limiter 16, which is embedded in the recess 6a, into a shape that matches the outer peripheral surface of the support 6, so that no step is generated at the upper end, thus preventing the accumulation of dust or liquid.

[0052] In this embodiment, the limiter 16 is formed of a metal material, but any type of material can be used. Alternatively, resin materials such as plastic or rubber can be used instead of metal.

[0053] In addition, the kinetic energy of the first arm 3 can be absorbed by the deformation of the limiter 16 caused by the contact of the first arm 3. However, the kinetic energy can also be reduced by braking the motor by detecting the impact of the contact between the first arm 3 and the limiter 16.

[0054] In addition, in this embodiment, the support column 6 is formed into a cylindrical shape, but it can also be formed into any other arbitrary cylindrical shape.

[0055] Alternatively, an opening 17 may be provided on the bottom surface of the recess 6a, but the opening 17 may also be omitted. By eliminating the opening 17, the limiter 16 can be supported on the entire bottom surface of the recess 6a, which is suitable for cases where the limiter 16 is made of a low-rigidity elastic material or the like.

[0056] Furthermore, although a limiter 16 for stopping the first arm 3, which rotates relative to the base 2 about the first axis A, is shown in this embodiment, the same structure can also be used for a limiter 24 for stopping the second arm 4 relative to the first arm 3.

[0057] That is, such as Figure 1 As shown, a hollow support column 23 is erected parallel to the second axis B from the lower surface of the second arm 4 downwards. The end face of the support column 23 and the lower surface of the first arm 3 are connected by a hollow connecting part 25. On both sides of the support column 23, limiters 24 are respectively assembled to abut against the side of the first arm 3 when the second arm 4 rotates relative to the first arm 3 beyond the rotation angle range.

[0058] like Figure 1 As shown by the dashed line, the line body 20 passes through the first arm 3 and is connected to the motor 13 or the motor for the ball screw spline shaft of the second arm 4, which is located in the second arm 4, via the internal space of the connecting part 25 and the support column 23. In the figure, reference numeral 26 is the reducer.

[0059] Explanation of reference numerals in the attached figures:

[0060] 1. Robot (Multi-joint robot)

[0061] 2 bases

[0062] 3. First arm (arm)

[0063] 6 pillars

[0064] 16 limit switches

[0065] 17 Opening

[0066] 20-line font

[0067] 21 Gasket (Sealing Component)

[0068] A. First axis (axis)

Claims

1. A multi-joint robot, characterized in that, have: Base; An arm, which is supported to be able to rotate about a specified axis within a rotational angle range of less than ±180° relative to the base; and A hollow support column, which rises from the base parallel to the axis outside the range of the arm's rotation angle; Linear elements are routed from the base to the arm through the interior of the support column. The aforementioned multi-joint robot is equipped with a limiter embedded in the side of the support column. When it comes into contact with the side of the arm that has rotated beyond the range of the rotation angle, it absorbs kinetic energy by deformation.

2. The multi-joint robot according to claim 1, characterized in that, The limiter is detachably mounted on the side of the support column.

3. The multi-joint robot according to claim 2, characterized in that, An opening penetrating the interior space of the pillar is provided on its side. The limiter is installed in a position that closes the opening.

4. The multi-joint robot according to claim 3, characterized in that, The multi-joint robot has a sealing member that is clamped between the limiter and the support column to seal the opening around its entire circumference.

5. The multi-joint robot according to any one of claims 1-4, characterized in that, One of the sides of the arm or the surface of the limiter has a convex shape that protrudes outward at a midway point along the axis, and the other has a flat shape without any protrusions or indentations along the axis.

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