POSITIONER

Abstract

The positioner (10) comprises: a base (20) with a pair of support parts (21), (22) arranged with a predetermined gap between them in the direction of the first axis (A); a shaft element (30) arranged between the pair of support parts and mounted for rotation about the first axis relative to the base;and a disc-shaped rotary table (50) which is mounted for rotation about a second axis (B) orthogonal to the first axis relative to the shaft element and has a mounting surface (51) on which a workpiece (W) can be attached, wherein the rotary table has an outer diameter dimension which fits inwards from both ends of the shaft element in the direction of the first axis, and in a range of movement of the rotary table about the first axis, a distance of the mounting surface from the first axis is set such that it is greater than a distance of an outermost edge about the first axis of at least one of the support parts from the first axis, and a distance of a rear surface of the mounting surface of the rotary table from the first axis is set such that it is less than the distance of the outermost edge from the first axis.

Description

Positioner

[0001] The present disclosure relates to a positioner.

[0002] A rotary table device is known that can rotate a supported workpiece around a tilt axis extending horizontally and around a rotation axis perpendicular to the tilt axis, thereby changing the posture of the workpiece around two axes (see, for example, Patent Document 1).

[0003] This rotary table device includes a rotary table that fixes a workpiece and rotates it about a rotation axis, and a tilting table that supports the rotary table so that it can rotate about a tilting axis.

[0004] Japanese Utility Model Application Laid-Open Publication No. 06-000625

[0005] If the surface of the rotary table is placed close to the tilt axis, the workpiece mounted on the rotary table may interfere with the components around the tilt table. For this reason, the size of the workpiece attached to the rotary table is limited so that it does not protrude too far from the rotary table. On the other hand, the farther the rotary table is placed from the tilt axis, the greater the moment and inertia around the tilt axis. Therefore, there is a demand for a positioner that can minimize the moment and inertia generated when a workpiece is rotated, without restricting the size of the workpiece.

[0006] One aspect of the present disclosure is a positioner comprising: a base having a pair of support parts arranged at a predetermined interval in a first axial direction; an axial member arranged between the pair of support parts and supported on the base so as to be rotatable about the first axis; and a circular rotary table rotatably supported on the axial member about a second axis perpendicular to the first axis and having a mounting surface on which a workpiece can be attached, wherein the rotary table has an outer diameter dimension that fits inside both ends of the axial member in the first axial direction, and within the movable range of the rotary table about the first axis, the distance of the mounting surface from the first axis is set to be greater than the distance from the first axis of the outermost edge of at least one of the support parts about the first axis, and the distance from the first axis of the back side of the mounting surface of the rotary table is set to be smaller than the distance from the first axis of the outermost edge.

[0007] Fig. 3 is a perspective view showing an outline of a positioner according to an embodiment of the present disclosure; Fig. 4 is a longitudinal sectional view of the positioner of Fig. 1; Fig. 5 is a side view of the positioner of Fig. 3; Fig. 6 is a side view of the positioner of Fig. 3 in a state where the shaft member is rotated 90° about a first axis; Fig. 7 is a view of the shaft member of the positioner of Fig. 1 from the rear side opposite to the rotary table; Fig. 8 is a longitudinal sectional view showing a modified example of the positioner of Fig. 1;

[0008] A positioner 10 according to an embodiment of the present disclosure will be described below with reference to the drawings. As shown in Fig. 1, the positioner 10 according to this embodiment includes a base 20 that is installed on a horizontal installation surface such as a floor, and a shaft member 30 that is supported rotatably relative to the base 20 about a horizontal first axis A. The positioner 10 also includes a first drive mechanism 40 that rotates the shaft member 30 about the first axis A relative to the base 20.

[0009] Furthermore, the positioner 10 includes a rotary table 50 supported on the shaft member 30 so as to be rotatable about a second axis B perpendicular to the first axis A, and a second drive mechanism 60 that rotationally drives the rotary table 50. As shown in Fig. 2, the positioner 10 also includes a power cable 70 that connects the rotary table 50 to an external power supply (not shown).

[0010] The base 20 includes a bottom 23 that is placed on an installation surface, and flat support portions 21 and 22 that protrude upward from the bottom 23. The support portions 21 and 22 are arranged parallel to each other and spaced apart in the direction of the first axis A. As shown in FIG. 3 , the upper end surfaces of the support portions 21 and 22 have a cylindrical outer surface shape with the first axis A as the central axis.

[0011] 2, the support portions 21 and 22 are provided with through holes 21h and 22h, respectively, that penetrate along the first axis A. The base 20 is provided with sleeves 24 and 25 that are fitted into the through holes 21h and 22h, respectively. The sleeves 24 and 25 are provided with inner holes 24h and 25h, respectively.

[0012] As shown in Fig. 2, the shaft member 30 is a shaft-shaped member having a longitudinal axis, and includes end portions 31, 32 on both sides in the longitudinal axis direction, and a central portion 33 disposed between the end portions 31, 32. The end portion 31 is supported rotatably about a first axis A relative to the sleeve 24. The end portion 32 is supported rotatably about the first axis A relative to the sleeve 25 by a first reducer (reduction gear) 42 (described later) attached between the end portion 31 and the sleeve 25. As a result, the shaft member 30 is supported in a doubly supported beam-like manner between the support portions 21, 22, with the longitudinal axis aligned along the first axis A.

[0013] 2, the outer diameter of the end portions 31, 32 about the first axis A is set to be larger than the outer diameter of the central portion 33 about the first axis A. Furthermore, the end portion 31 is provided with a protrusion 34, which is a portion of the outer circumferential surface that protrudes radially outward, at a circumferential position along the second axis B. The tip surface of the protrusion 34 is located on the end portion 31 side at the outermost edge of the shaft member 30 about the first axis A.

[0014] Furthermore, when the shaft member 30 rotates around the first axis A by a predetermined angle, for example, exceeding ±90° from a position where the second axis B is disposed vertically, the protrusion 34 abuts against the stopper 26 provided on the support portion 21. As a result, the protrusion 34 and the stopper 26 restrict the operating range of the shaft member 30 to ±90°.

[0015] The end portion 31 is provided with a hollow portion (first hollow portion) 31h extending from the end face along the first axis A. The sleeve 24 is inserted into the hollow portion 31h from the end face side, and a bearing 11 is disposed between the outer peripheral surface of the sleeve 24 and the inner peripheral surface of the hollow portion 31h. This allows the end portion 31 to be rotatably supported around the first axis A relative to the sleeve 24. The hollow portion 31h opens on the side opposite the turntable 50 (hereinafter also referred to as the back side) closer to the center portion 33 than the portion supported by the bearing 11. This forms a hollow path 35 that passes from the outside of the support portion 21 in the first axis A direction through the inner hole 24h of the sleeve 24 and the hollow portion 31h to the back side of the shaft member 30.

[0016] The central portion 33 has a shape recessed along the second axis B toward the first axis A, and has a cylindrical inner surface around the second axis B.

[0017] The first drive mechanism 40 includes a first motor 41 fixed to the support portion 22 of the base 20, and a first reducer 42 that reduces the rotation of a motor shaft 41 a of the first motor 41 and transmits the reduced rotation to the shaft member 30. The first motor 41 is fixed to the outer surface side of a sleeve 25 that is fitted into a through-hole 22 h of the support portion 22. The motor shaft 41 a of the first motor 41 passes through an inner hole 25 h of the sleeve 25 from the outside and is disposed along the first axis A.

[0018] The first reducer 42 includes a fixed portion 43 fixed to the inner surface side of the sleeve 25, and an output portion 44 that can be rotated about the first axis A relative to the fixed portion 43. A plurality of gears (not shown) including a gear that meshes with a gear 45 fixed to the motor shaft 41 a are housed inside the first reducer 42. The output portion 44 is fixed to the end face of the end portion 32 of the shaft member 30. As a result, the rotation of the motor shaft 41 a of the first motor 41 is reduced in speed by the first reducer 42 and transmitted to the end portion 32.

[0019] The outer peripheral surface of the output portion 44 is the outermost edge of the first reducer 42 around the first axis A on the end portion 32 side. The outer peripheral surface of the output portion 44 is also located radially outward from the upper end surfaces of the support portions 21 and 22 and the tip surfaces of the protrusions 34 of the shaft member 30, centered on the first axis A. In other words, the outer peripheral surface of the output portion 44 is located at the outermost edge of the first reducer 42, the shaft member 30, and the base 20 around the first axis A.

[0020] The rotary table 50 is formed in a disk shape from a conductive material and has a mounting surface 51 on which the workpiece W is attached. The rotary table 50 is disposed in a position where its central axis coincides with the second axis B, and is supported by a second reducer 62 (described later) to be rotatable about the second axis B relative to the shaft member 30.

[0021] 2, the outer diameter of the turntable 50 is set to a size that fits inside the ends 31 and 32 in the direction along the first axis A. That is, the turntable 50 is disposed at a position that does not overlap with the ends 31 and 32 in the direction along the first axis A. The distance from the first axis A of the mounting surface 51 of the turntable 50 to the first axis A is set to be slightly larger than the outer diameter of the outer peripheral surface of the output portion 44. On the other hand, the distance from the first axis A of the back surface 52 of the turntable 50 to the first axis A is set to be smaller than the outer diameter of the outer peripheral surface of the output portion 44, as shown in FIGS.

[0022] As shown in Fig. 5, the second drive mechanism 60 includes a second motor 61 fixed to the shaft member 30 at a position offset parallel to the second axis B. As shown in Fig. 2, the second drive mechanism 60 also includes a second reducer 62 that reduces the rotation of a motor shaft (not shown) of the second motor 61 and transmits the reduced rotation to the rotary table 50. Furthermore, the second drive mechanism 60 includes a protective cover 65 fixed to the shaft member 30 and surrounding the periphery of the second motor 61.

[0023] The second reducer 62 is disposed between the central portion 33 of the shaft member 30 and the rotary table 50. The second reducer 62 is fixed to the central portion 33, and reduces the rotation of the motor shaft of the second motor 61 before transmitting the rotation to the rotary table 50, thereby rotating the rotary table 50 around the second axis B relative to the shaft member 30.

[0024] Furthermore, a hollow portion (second hollow portion) 63 penetrating along the second axis B is provided in a region including the second axis B in the turntable 50, the second reducer 62, and the central portion 33 of the shaft member 30. One end of the hollow portion 63 in the direction of the second axis B opens toward the mounting surface 51 of the turntable 50, and the other end opens toward the back surface of the shaft member 30. As shown in FIG. 2 , an adapter 55 made of a conductive material is detachably fixed from the mounting surface 51 side to the opening of the hollow portion 63 on the turntable 50 side, at a position that closes the opening. The adapter 55 is provided with a terminal 56 to which a power cable 70 is connected.

[0025] One end of the power cable 70 is connected to the terminal 56 of the adapter 55, and the other end is connected to a distribution box 71 installed on the side of the support portion 22. As a result, for example, when the distribution box 71 is connected to an external welding power source (power supply device) not shown, the rotary table 50 is connected to the negative electrode via the power cable 70 and the adapter 55.

[0026] The operation of the positioner 10 according to this embodiment configured as described above will be described below. For example, when arc welding is performed on a workpiece W using a welding robot (not shown), the positioner 10 according to this embodiment is first installed at a predetermined position within the working area of ​​the welding robot. Then, the workpiece W is attached to the mounting surface 51 of the rotary table 50 of the positioner 10.

[0027] Next, the power distribution box 71 fixed to the side surface of the support portion 22 of the base 20 is connected to an external welding power source. This connects the negative electrode to the workpiece W via the power cable 70, adapter 55, and rotary table 50. Also, the welding torch fixed to the tip of the wrist of the welding robot is connected to the positive electrode of the welding power source. Then, the welding robot is operated with the tip of the welding torch brought close to the surface of the workpiece W at a predetermined distance. This generates an arc between the workpiece W and the welding torch, allowing the workpiece W to be welded.

[0028] In this case, when the first motor 41 is operated, the rotation of the motor shaft 41a is reduced by the first reducer 42 and transmitted to the shaft member 30. The shaft member 30 is then rotated around the first axis A relative to the base 20. When the second motor 61 is operated, the rotation of the motor shaft of the second motor 61 is reduced by the second reducer 62 and transmitted to the turntable 50. As a result, the turntable 50 is rotated around the second axis B relative to the shaft member 30.

[0029] This allows the posture of the workpiece W to be changed around the first axis A and the second axis B. In other words, the position of the surface of the workpiece W that the tip of the welding torch approaches can be changed around two axes, allowing the desired location of the workpiece W to be welded.

[0030] In this embodiment, the turntable 50 is positioned so as not to overlap the ends 31, 32 of the shaft member 30 in the direction along the first axis A. Therefore, as shown in FIG. 3 , the area of ​​the turntable 50 near the central axis of the back surface 52 is closer to the first axis A than the outer peripheral surface of the output portion 44.

[0031] That is, compared to when the entire rotary table 50 is disposed radially outward from the outer circumferential surface of the output portion 44 about the first axis A, the mounting surface 51 can be brought closer to the first axis A. This allows the workpiece W, which is a heavy object to be mounted on the mounting surface 51, to be placed closer to the first axis A.

[0032] By bringing the workpiece W close to the first axis A, it is possible to reduce the rotational moment and inertia about the first axis A acting on the rotary table 50 when the shaft member 30 is rotated about the first axis A. As a result, it is possible to improve the positioning accuracy of the workpiece W about the first axis A and reduce the load on the motor shaft 41 a of the first motor 41.

[0033] 3 and 4 , throughout the entire movable range of the rotary table 50 about the first axis A, the mounting surface 51 is always positioned radially outward from the outer circumferential surface of the output portion 44 in the direction centered on the first axis A. In other words, the first reducer 42, the shaft member 30, and the support portions 21 and 22 are not positioned on the movement path of the workpiece W placed on the mounting surface 51. This prevents the workpiece W from interfering with the components of the positioner 10 when the orientation of the workpiece W is changed about the first axis A.

[0034] As described above, according to this embodiment, the workpiece W attached to the rotary table 50 can be placed in a position that does not interfere with the positioner 10, while being brought close to the first axis A. In other words, the rotational moment and inertia when the workpiece W is rotated around the first axis A can be kept small without restricting the size of the workpiece W attached to the rotary table 50.

[0035] 2, the power cable 70 in this embodiment is led from the distribution box 71 to the outside of the support portion 21, for example, along the bottom portion 23 of the base 20. Then, at a position where the power cable 70 is curved upward along the support portion 21, the power cable 70 is fixed to the support portion 21 by a first clamp 81, and then introduced from the outside of the support portion 21 into the hollow path 35.

[0036] The power cable 70 introduced into the hollow path 35 extends along the first axis A in the vicinity of the first axis A within the hollow path 35, and is fixed to the shaft member 30 by the second clamp 82 at a position where it passes through the hollow portion 31h of the shaft member 30. The power cable 70 is then bent in a direction away from the rotary table 50, and then bent approximately 180° into a U-shape. The power cable 70 then extends along the second axis B and is introduced into the hollow portion 63, with one end being detachably fixed to the terminal 56 provided on the adapter 55.

[0037] In this case, when the shaft member 30 is rotated about the first axis A relative to the base 20, the relative positions of the first clamp 81 and the second clamp 82 about the first axis A are changed in accordance with the rotation. As a result, the power cable 70 between the first clamp 81 and the second clamp 82 is twisted about the first axis A accompanied by bending deformation about the first axis A. On the other hand, the power cable 70 between the second clamp 82 and the terminal 56 is not deformed because it is rotated about the first axis A integrally with the shaft member 30.

[0038] Furthermore, when the rotary table 50 is rotated relative to the shaft member 30 about the second axis B, a torsional force acts on the power cable 70 about the second axis B. As a result, torsional deformation and bending deformation about the second axis B occur in the U-shaped excess length of the power cable 70 between the second clamp 82 and the terminal 56.

[0039] Furthermore, the torsional force acting on the power cable 70 around the second axis B due to the rotation of the turntable 50 around the second axis B is blocked by the second clamp 82. Therefore, the power cable 70 on the first clamp 81 side of the second clamp 82 does not deform.

[0040] By using such wiring, it is possible to differentiate the portion of the power cable 70 that is deformed by the rotation of the shaft member 30 about the first axis A from the portion that is deformed by the rotation of the turntable 50 about the second axis B. This makes it possible to prevent the movements of the power cable 70 from being combined and causing it to move wildly, even when the rotation of the shaft member 30 about the first axis A and the rotation of the turntable 50 about the second axis B are performed simultaneously.

[0041] Furthermore, when the shaft member 30 and the rotary table 50 are rotated about their respective axes, not only torsional deformation but also bending deformation can be generated in the power cable 70. This has the advantage of being able to effectively absorb the torsional force acting on the power cable 70.

[0042] In this embodiment, the power cable 70 between the second clamp 82 and the terminal 56 is deformed as the turntable 50 rotates about the second axis B. Alternatively, the power cable 70 may be configured to maintain its position even when the turntable 50 rotates about the second axis B.

[0043] 6, for example, an adapter 55 equipped with a cylindrical shaft 57 made of a conductive material and a rotary joint 58 attached to the shaft 57 is attached to a rotary table 50. In addition, current collecting brushes 90 are attached to the back side of the central portion 33 of the shaft member 30 at two locations spaced apart in the circumferential direction around the second axis B.

[0044] The current collecting brush 90 includes a carbon brush portion 91 and a pressing portion 92 that presses the brush portion 91 against the outer circumferential surface of the shaft 57. The pressing portion 92 is fixed to the rear surface of the central portion 33, so that the pair of brush portions 91 sandwich the outer circumferential surface of the shaft 57 from the radially outer side. In this case, the tip of the power cable 70 is connected to terminals (not shown) provided on the pair of brush portions 91.

[0045] In this configuration, when the turntable 50 is rotated about the second axis B, the shaft 57 rotates together with the turntable 50 about the second axis B. On the other hand, the current collecting brush 90 does not rotate about the second axis B, and the brush portion 91 maintains contact with the outer circumferential surface of the shaft 57.

[0046] Therefore, even if the turntable 50 rotates infinitely around the second axis B, the turntable 50 can continue to be connected to the negative electrode while maintaining the orientation of the power cable 70. Also, even when the shaft member 30 is rotated around the first axis A, only the portion of the power cable 70 between the first clamp 81 and the second clamp 82 is deformed, and the portion of the power cable 70 from the second clamp 82 to the tip side is not deformed.

[0047] This allows the excess length of the power cable 70 on the tip side of the second clamp 82 to be minimized, thereby enabling the power cable 70 to be shortened and the positioner 10 to be made smaller overall.

[0048] In addition, in this embodiment, the outer peripheral surface of the output portion 44 of the first reducer 42 is the outermost edge of the positioner 10 around the first axis A within the movable range of the rotary table 50. Alternatively, another component may be disposed at the outermost edge of the positioner 10 around the first axis A.

[0049] For example, the protrusion 34 provided on the end portion 31 of the shaft member 30 may protrude radially outward about the first axis A beyond the outer peripheral surface of the output portion 44. In this case, the tip surface of the protrusion 34 becomes the outermost edge of the positioner 10 about the first axis A, and therefore the mounting surface 51 may be positioned slightly radially outward about the first axis A beyond the tip surface of the protrusion 34. This makes it possible to suppress the rotational moment and inertia about the first axis A in the same manner as above, without restricting the size of the workpiece W to be attached to the rotary table 50.

[0050] Similarly, the upper end surfaces of the support portions 21, 22 may be disposed radially outward about the first axis A from the outer circumferential surface of the output portion 44 and the tip surfaces of the protrusions 34. In this case, the mounting surface 51 may be disposed slightly radially outward about the first axis A from the upper end surfaces of the support portions 21, 22. In this case, the upper end surfaces of the support portions 21, 22 may have an outer surface shape consisting of half the circumference of a cylinder whose central axis is the first axis A and whose radius is slightly shorter than the distance from the first axis A to the mounting surface 51.

[0051] In this embodiment, an adapter member having a larger diameter than the rotary table 50 may be interposed between the mounting surface 51 of the rotary table 50 and the workpiece W. This allows the workpiece W to be supported over a surface that is larger than the mounting surface 51 of the rotary table 50.

[0052] Furthermore, the positioner 10 in this embodiment includes the power cable 70 that connects the negative electrode to the rotary table 50. In addition, the positioner 10 may include a pipe that supplies a fluid such as pressurized air to the rotary table 50. In this case, the pipe that supplies the fluid to the rotary table 50 may be routed along the same path as the power cable 70. Furthermore, the pipe may be fixed together with the power cable 70 by a first clamp 81 and a second clamp 82.

[0053] Although the embodiments of the present disclosure have been described in detail above, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible to these embodiments without departing from the gist of the invention or the concept and spirit of the present invention derived from the content of the claims and their equivalents. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these.

[0054] REFERENCE SIGNS LIST 10 Positioner 20 Base 21 Support portion 21h Through hole 22 Support portion 22h Through hole 30 Shaft member 31h Hollow portion (first hollow portion) 42 First reducer (reduction gear) 50 Rotary table 51 Mounting surface 52 Back surface 62 Second reducer 63 Hollow portion (second hollow portion) 70 Power cable 81 First clamp 82 Second clamp A First axis B Second axis W Workpiece

Claims

1. A positioner comprising: a base having a pair of support parts arranged at a predetermined interval in the direction of a first axis; a shaft member arranged between the pair of support parts and supported on the base so as to be rotatable about the first axis; and a circular rotary table rotatably supported on the shaft member about a second axis perpendicular to the first axis and having a mounting surface on which a workpiece can be attached, the rotary table having an outer diameter dimension that fits inside both ends of the shaft member in the direction of the first axis, and within the movable range of the rotary table about the first axis, the distance of the mounting surface from the first axis is set to be greater than the distance from the first axis of the outermost edge about the first axis of at least one of the support parts, and the distance from the first axis of the back side of the mounting surface of the rotary table is set to be smaller than the distance from the first axis of the outermost edge.

2. A positioner as described in claim 1, further comprising a reducer disposed between one of the support parts and one end of the shaft member, which supports the shaft member rotatably about the first axis relative to the support part, wherein the distance from the first axis of the outer surfaces of the shaft member and the reducer in the second axial direction is set to be smaller than the distance from the first axis of the mounting surface, and the distance from the first axis of the back surface is set to be smaller than the distance from the first axis of the outer surface.

3. A positioner according to claim 1 or claim 2, wherein a portion of the outer peripheral surface of at least one of said support portions about said first axis is formed by a cylindrical surface about said first axis.

4. A positioner as described in claim 1 or claim 2, comprising: a power cable connecting the rotary table to an external power supply; and a second reducer connecting the shaft member and the rotary table so that they can rotate relative to each other about the second axis, one of the support parts having a through hole that passes through along the first axis, the shaft member having a first hollow portion that communicates with the through hole, and the second reducer having a second hollow portion that extends along the second axis, wherein the power cable is guided along one of the support parts toward the first axis, fixed to the outer surface of one of the support parts by a first clamp, introduced into the first hollow portion via the through hole, and fixed to the shaft member by a second clamp at a position bent in a direction away from the rotary table, then bent with excess length, passes through the second hollow portion along the second axis, and one end is connected to the rotary table.

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