JP4246776B2 - Single axis robot - Google Patents

Description

  The present invention relates to a so-called single-axis robot.

  2. Description of the Related Art Conventionally, a single-axis robot has been known that has a movable member that can be moved in one axial direction by driving a motor, and that is configured to be used with various tools mounted on the movable member.

In this type of single-axis robot, a movable member is mounted on a rail, and a ball screw shaft provided parallel to the rail is screwed through a nut portion provided on the movable member, and the ball screw shaft is driven to rotate by a motor. In general, the movable member is moved along the rail. In recent years, as a modification of such a drive mechanism, there is also a type in which a hollow motor is mounted on a movable member and the nut portion is integrally provided on the rotor, and the movable member is moved by rotationally driving the nut portion by the hollow motor. It has been proposed (for example, Patent Document 1).
JP-A-8-168980

  According to the configuration in which the motor is mounted on the movable member and the nut portion is driven as described above, it is not necessary to dispose the motor at the end portion of the screw shaft as in the configuration in which the ball screw shaft is rotationally driven. Even a single-axis robot has an advantage that the movable range of the movable member can be widened (longened).

  However, on the other hand, in the configuration such as Patent Document 1, for example, a hollow motor is integrated into the movable member, and a nut portion is provided integrally with the rotor of the motor. The motor alone cannot be removed from the movable member, and it is necessary to temporarily remove the ball screw shaft and the movable member attached thereto and disassemble the movable member to repair or replace the motor. Therefore, there is a problem that the maintainability is extremely poor. In particular, this type of single-axis robot is used by mounting various tools on a movable member, and by constructing an XY biaxial robot by assembling another single-axis robot to the movable member. When trouble occurs, it is necessary to remove the tool. In this case, there is an inconvenience that the operation using the robot is stopped for a long time. Therefore, it is required to improve this point.

  In a single-axis robot, a pair of movable members may be mounted on a common ball screw shaft, and each movable member may be driven individually. In such a robot, maintenance of one movable member is performed. In some cases, the other movable member may interfere with the work. Therefore, this point needs to be taken into consideration when improving maintainability.

  The present invention has been made in view of such circumstances, and an object thereof is to improve the maintainability of a single-axis robot in which a hollow motor is mounted on a movable member.

In order to solve the above-described problems, the single-axis robot of the present invention is configured so that various tools can be mounted, and a pair of movable units that are movably mounted on the rail in a state of being aligned in a line along the rail. comprising a member, and a screw shaft of one that is parallel with the rails, to the each movable member is screwed attached to the screw shaft and is supported so as to rotate relative to the screw axis And a hollow motor that is arranged so that the screw shaft passes through the nut member and rotationally drives the nut member, and each movable member moves along the rail by driving the nut member. a uniaxial robot for the hollow motor, and a housing for rotatably holding the rotor and hollow shaft-shaped rotor in which the screw shaft passes, wherein relative to said nut member The rotor is detachably connected to the nut member, and the housing is detachably fixed to the movable member. by releasing the fixed state of the housing relative to the connecting state and the movable member, in shall be configured to displacement is permitted in a direction away from the nut member and the direction along the threaded shaft (Claim 1).

  According to such a configuration, since the hollow motor can be pulled out independently from each movable member along the screw shaft, the motor can be repaired without removing the movable member and various tools assembled to the movable member. Exchange can be performed.

In the single-axis robot as described above, the screw shaft is fixed to the shaft support portion with both ends thereof supported by the shaft support portion, and the shaft support is released by releasing the fixed state. It is preferable that it is slidable in the axial direction with respect to the portion (claim 2 ). More specifically, by releasing the fixed state and sliding the screw shaft in the axial direction, between either one of the shaft support portions and the end of the screw shaft, It is preferable that a gap is formed so that a hollow motor on one side of the pair of movable members can be attached and detached (Claim 3 ).

  According to such a configuration, the hollow motor can be easily taken out between the end portion of the screw shaft and the shaft support portion by sliding (sliding) the screw shaft in the axial direction with respect to the shaft support portion. Is possible.

In the single-axis robot as described above, the movable member is a nut member on the side closer to the other of the movable member in the axial direction of the screw shaft, is disposed, respectively Re said hollow motor pixel on the far side It is preferable to have a configuration (claim 4 ).

  According to such a configuration, the hollow motor of each movable member can be removed on the side away from each other, so that the other movable member does not get in the way when the motor is removed from the movable member, and maintenance is good. It will be a thing.

In a single-axis robot that is not fixed to the shaft support portion with both ends of the screw shaft supported by the shaft support portion, the fixed state is released and the screw shaft is slid in the axial direction. Accordingly, the between the end of the screw shaft and either side of the shaft support portions may be one gap is formed to allow desorption of said movable member (claim 5) .

Further, in the single-axis robot as described above, detection means for detecting rotational position information of the hollow motor is assembled to each movable member, and each detection means is arranged in the axial direction of the screw shaft. more preferred said hollow motor across the nut member is coupled to the nut member is arranged on the opposite position (claim 6).

  According to this configuration, the detection means can be pulled out from the movable member alone in the axial direction to be repaired or exchanged, so that maintainability is also improved in this respect.

  According to the single-axis robot of the present invention, it becomes possible to repair or replace the hollow motor by pulling it alone from the movable member in the screw axis direction. Therefore, it becomes possible to perform maintenance of the hollow motor or the like without removing the movable member and various tools assembled thereto, and thereby maintainability can be remarkably improved.

  A preferred embodiment of the present invention will be described with reference to the drawings.

  1 to 4 schematically show a single axis robot having a single movable member (movable table 10) as a base for a single axis robot according to the present invention, and FIG. 1 is a longitudinal sectional view. FIG. 2 is a plan view, and FIGS. 3 and 4 are cross-sectional views each showing a single-axis robot.

  As shown in these drawings, the single-axis robot has an elongated casing 1, a movable table 10 (corresponding to a movable member according to the present invention) in the casing 1, and this is moved in a uniaxial direction. For this reason, the drive mechanism is housed.

  The casing 1 includes a base 2 elongated in a uniaxial direction, end covers 3 fixed to both ends in the longitudinal direction of the base 2, side covers 4 fixed to both ends in the width direction of the base 2, and a top covering the base from above. It has a hollow structure composed of a cover 5 (shown in FIGS. 3 and 4).

  Each of the covers 3 to 5 is configured to be detachable from the base 2 with bolts or the like, and the inside can be opened by removing these covers 3 to 5 during maintenance or the like. In the following description, for the sake of convenience, the moving direction of the movable table 10 (longitudinal direction of the casing 1) is referred to as the front-rear direction, and the direction orthogonal thereto is referred to as the width direction.

  As shown in FIG. 3, the base 2 has a U-shaped cross section with a concave central portion in the width direction, and has flat rail support surfaces 2 a extending in the front-rear direction at protruding portions at both ends.

  Rails 14 extending in the front-rear direction are fixed to these rail support surfaces 2a in parallel with each other. The movable table 10 is mounted on the rails 14 via a slider 13, whereby the movable table 10 is provided so as to be movable in the uniaxial direction (front-rear direction).

  As shown in FIGS. 2 and 3, the movable table 10 has tool attachment portions 11 extending in the front-rear direction at both ends in the upper width direction. As shown in FIG. 3, these tool attachment portions 11 are formed in slits formed in the casing 1, that is, from a gap portion in the front-rear direction formed between the top cover 5 and the side cover 4 (both omitted in FIG. 2). It protrudes outside the upper part of the casing 1, and various tools can be assembled to this part. In FIG. 2, reference numeral 11 a indicates a tool assembly screw hole provided in the tool attachment portion 11.

  The driving mechanism of the movable table 10 includes the pair of rails 14, a ball screw shaft 15 extending in parallel with the rails 14, and a nut member 16 that is assembled to the movable table 10 and screwed onto the ball screw shaft 15. And a hollow motor 25 or the like that is assembled to the movable table 10 and rotationally drives the nut member 16. That is, the nut member 16 is rotated forward and backward by the hollow motor 25 so that the movable table 10 is moved along the rail 14 in the front-rear direction along with the rotation.

  Here, a more detailed structure of the movable table 10 will be described.

As shown in FIGS. 3 and 5, the movable table 10 is integrally provided with a fixed portion 12 of the hollow motor 25 on the lower side thereof. The fixing portion 12 has a hollow structure provided with a mounting surface 121 of the hollow motor 25 on one end side (right side in FIG. 5), and the nut member 16 is provided inside the fixing portion 12. The hollow motor 25 is assembled to the mounting surface 121 from the outside of the fixed portion 12 so as to be aligned in a line in the front-rear direction with respect to the member 16.

  The nut member 16 includes a ball nut 17 that is screwed onto the ball screw shaft 15 and a nut holder 18 that is integrally fitted and fixed to the outside of the nut member 16. As shown in FIG. The fixed part 12 is rotatably supported.

  A coupling 20 for connecting the nut member 16 and the hollow motor 25 is further provided inside the fixing portion 12, and a nut holder 18 is connected and fixed to one end side of the coupling 20. The coupling 20 has slotted insertion holes at both ends, and as shown in FIG. 5, a sleeve 18a formed integrally with the nut holder 18 is on one end side of the coupling 20 (the left side in the figure). The nut member 16 is coupled and fixed to the coupling 20 by fastening bolts (not shown) so that the slit is narrowed in this state.

  As shown in the figure, the hollow motor 25 has a configuration in which a motor main body 28 and a position detector 38 for detecting rotational position information are integrally provided in a common housing 26.

  The motor main body 28 includes a casing 30a and a stator 30A composed of a field coil (driving coil) 31b provided inside the casing 31a, and a rotor 30B disposed inside the stator 30A. As shown in the figure, the rotor 30B has a structure in which a magnet 32 is fixed to the outer peripheral surface of the hollow shaft 34, and both front and rear end portions are connected to the front portion 26a and the rear portion of the housing 26 via bearings 35a and 35b. By being supported in the side portion 26b, it is rotatably supported inside the stator 30a. The tip (left end in the figure) of the rotor 30B (hollow shaft 34) is provided so as to protrude forward from the housing 26.

  On the other hand, the position detector 38 is disposed on the rear side (right side in FIG. 5) of the motor main body 28, specifically, on the rear side of the rear bearing 35b that supports the rotor 30B.

  The position detection unit 38 includes an output side winding (stator portion 40A) and a magnetic excitation side winding (rotor portion 40B), and is induced by magnetizing the rotor portion 40B with an AC voltage. As shown in the figure, the rotor portion 40B is composed of the rotor 30B (hollow shaft 34) of the motor main body 28. On the outer periphery of the rear end, the stator portion 40A is fixed to the rear portion 26b of the housing 26 holding the bearing 35b. Thus, the rotation angle (position in the rotation direction) of the motor main body 28, that is, the rotation angle of the rotor 30B is detected.

  As shown in FIG. 5, in the hollow motor 25, the front end of the hollow shaft 34 of the motor body 28 is inserted into the front bearing 35a, while the rear end is inserted into the rear bearing 35b. The rear portion 26b of the housing 26 is united with the front portion 26a with the casing 31a interposed therebetween, and is fixed by fastening with a bolt (not shown).

Then, the rotor 30B of the motor main body 28 is inserted into the fixing portion 12 through the opening 12a formed in the mounting surface 121, and the fixing portion 12 is in a state where the front end surface of the housing 26 is abutted against the mounting surface 121. A hollow motor 25 is fixed to the front. Specifically, with the boss 26c formed on the front end surface of the housing 26 fitted in the opening 12a, as shown in FIG. Then, the bolt 27 is inserted into the fixing portion 12 by being screwed into a screw hole formed in the mounting surface 121. Then, the rotor 30B (hollow shaft 34) is inserted into the insertion hole on the opposite side of the coupling 20 from the nut member 16, and the bolt 22 (see FIG. 3) is tightened so that the slit is narrowed in this state. As a result, the nut member 16 and the hollow motor 25 (rotor 30B) are coupled via the coupling 20 so as to be able to transmit drive.

  In the movable table 10, a connecting portion between the nut member 16 and the hollow motor 25, that is, a portion corresponding to a fastening position of the bolt 22 or the like in the coupling 20 is provided with a tool hole accessible to the bolt 22 or the like from the outside. It has been. Specifically, as shown in FIGS. 2 and 3, a vertical tool hole 11 b that communicates the upper part of the movable table 10 and the inside of the fixed part 12, the side part of the fixed part 12, and the inside of the fixed part 12. A lateral tool hole 12b that communicates is provided. Thereby, before attaching various tools to the movable table 10, the top cover 5 is removed to remove the top cover 5 from the vertical tool hole 11b into the fixed portion 12, and after attaching various tools, the side cover 4 is removed. Therefore, the bolts 22 and the like can be operated by accessing the inside of the fixed portion 12 from the rail 14 side.

  Further, a heat radiation fin 11c (shown only in FIGS. 3 and 4) is provided on the upper surface portion of the movable table 10 and at a position corresponding to or near the mounting position of the hollow motor 25, that is, a portion corresponding to the fixed portion 12. It has been. Thereby, the heat dissipation effect of the movable table 10 is enhanced, and the drive heat of the hollow motor 25 and the nut member 16 is prevented from being transmitted to various tools assembled to the movable table 10.

  Note that the wires of the hollow motor 25, that is, the wires 28 a and 38 a that supply power and control signals to the motor main body 28 and the position detection unit 38, as shown in FIG. 13 is led out to the outside of the rail 14 through the rear side, and is connected to harnesses in the cable bear 42 laid on the side of the casing 1 via a connector or the like.

  Then, as shown in FIG. 5, the hollow motor 25 (rotor 30B (hollow shaft 34) with the ball screw shaft 15 screwed into the ball nut 17 is inserted into the movable table 10 configured as described above. )), Penetrating the coupling 20 and the nut member 16.

  As shown in FIG. 1, the ball screw shaft 15 is fixed to support blocks 23 (corresponding to a shaft support portion according to the present invention) provided at both front and rear ends of the base 2.

  More specifically, the support block 23 is fixed to the base 2 as shown in FIG. 7 and FIG. 7, and has a base block 23a having a through hole 44 penetrating in the front-rear direction, and the base block 23a. And a holder block 23b assembled from the front and rear outside. The holder block 23b is formed with a boss portion 45 having a recess for insertion of the ball screw shaft 15, and the holder block 23b is attached to the base block 23a with the boss portion 45 fitted in the through hole 44. The bolt 46 is fixed from the outside.

  Then, the end portion of the ball screw shaft 15 is inserted into the boss portion 45 of the holder block 23b, and the bolt 47 is screwed into the screw hole formed on the end surface of the ball screw shaft 15 from the outside of the holder block 23b. As a result, both ends of the ball screw shaft 15 are fixed to the support block 23, respectively.

  A slit is formed in the boss portion 45, and a bolt (not shown) is tightened so that the slit is narrowed in a state where the end portion of the ball screw shaft 15 is inserted into the boss portion 45. As a result, the ball screw shaft 15 is fixed to the holder block 23b (support block 23) while being prevented from rotating.

  Next, how to use the single axis robot described above will be described.

  According to the single-axis robot as described above, when the hollow motor 25 is driven, the rotational driving force is transmitted to the nut member 16 through the rotor 30B (hollow shaft 34) and the coupling 20, thereby the ball nut 17 is moved. It rotates relative to the movable table 10, and the movable table 10 moves in the front-rear direction along the rail 14 along with this rotation. Therefore, by assembling various tools to the tool mounting portion 11 of the movable table 10, it is possible to perform a predetermined operation while moving the tool in the uniaxial direction.

  Note that, for example, when trouble occurs in the hollow motor 25 during a predetermined operation using the tool (when the motor main body 28 or the position detection unit 38 breaks down), the hollow table 25 is hollowed from the movable table 10 according to the following procedure. By removing the motor 25, the motor 25 can be repaired.

  First, the bolt 22 of the coupling 20 is loosened, and the connection state between the nut member 16 and the hollow motor 25 is released. Specifically, the side cover 4 is removed, and a screwdriver or the like is inserted into the lateral tool hole 12b formed in the movable table 10 (fixed portion 12) from the side of the casing 1 as shown by a white arrow in FIG. Insert the tool and loosen the bolt 22. In this case, when the top cover 5 can be easily removed and the vertical tool hole 11b can be used in relation to the tool assembled to the movable table 10, the horizontal tool hole 12b is used. Instead of this, the bolt 22 may be loosened using the tool hole 11b.

  Next, a tool is inserted along the hollow motor 25 from the rear side of the movable table 10, the bolt 27 (see FIG. 4) fixing the hollow motor 25 is loosened, and then the hollow motor 25 is moved along the ball screw shaft 15. Pull it out from the fixing part 12 to the rear side. If it does in this way, as shown in FIG. 6, the hollow motor 25 can be removed to the rear side of the movable table 10 independently. Therefore, when performing simple repairs and operation checks of the hollow motor 25, the hollow motor 25 is completely removed from the single-axis robot by performing the operation with only the hollow motor 25 pulled out from the movable table 10 in this way. You can work without taking it out. At this time, since the electric wires 28a and 38a of the hollow motor 25 are led out to the outside of the rail 14 through the rear side of the slider 13 as described above, the electric wires 28a and 38a do not obstruct the removal. The hollow motor 25 can be quickly removed from the movable table 10.

  Unlike such minor repairs, when it is necessary to completely remove the hollow motor 25 from the casing 1 for repair, or when it is necessary to replace the hollow motor 25, the ends on both the front and rear sides are further reduced. Remove the cover 3. Then, the bolt 47 on either side of the support block 23 that fixes the ball screw shaft 15 is removed, and the bolt 46 that fixes the holder block 23b on the support block 23 on the opposite side is removed, The holder block 23b is pulled out from the base block 23a (slid in the axial direction). In this way, as shown in FIG. 7, a space is formed between the support block 23 on the side opposite to the drawing side (the right side in FIG. 7) and the end portion of the ball screw shaft 15. The hollow motor 25 can be replaced or the like by taking out the hollow motor 25 to the outside of the casing 1. At this time, even when the ball screw shaft 15 is pulled out as shown in FIG. 7, the movable table 10 is supported by the rails 14 so that the balance thereof is not lost. The hollow motor 25 can be removed while keeping this state.

  After repairing the hollow motor 25 in this manner, the hollow motor 25 is assembled to the movable table 10 in the reverse procedure to the above, and the ball screw shaft 15 is fixed to the front and rear support blocks 23 and the cover 4 is assembled. Repair of the hollow motor 25 is completed.

  According to the single-axis robot as described above, as described above, only the hollow motor 25 is pulled out along the ball screw shaft 15 from the movable table 10 without removing the movable table 10 and various tools assembled thereto. Repair and operation check.

  Moreover, even when the hollow motor 25 is completely removed from the casing 1 and replaced, as long as the holder block 23b is removed from the support block 23 and the ball screw shaft 15 is shifted in the axial direction as described above, the movable table The hollow motor 25 can be replaced without removing any of the tools 10 and various tools assembled thereto.

  Accordingly, when compared with a conventional single-axis robot of this type in which the movable table needs to be taken out and disassembled when the motor is repaired or replaced, the maintainability, particularly the workability of repairing or replacing the hollow motor 25 is significantly improved. Can do.

  The single-axis robot according to the present invention employs the following configuration based on the single-axis robot as described above.

  In other words, as shown in FIG. 8, two movable tables 10 are provided. Specifically, the two movable tables 10 are movably supported on a common rail 14 and a common ball screw shaft 15 is screwed through the nut member 16 of each movable table 10. Each movable table 10 was driven individually. According to such a configuration, since the tools can be mounted on the two movable tables 10 and moved individually, there is an effect that the application of the single-axis robot can be expanded.

  In the case of this configuration, each movable table 10 is movable so that the hollow motors 25 of the movable tables 10 are separated from each other (so that the support blocks 16 face each other in the front-rear direction), as shown in FIG. A table 10 is preferably provided. In this way, since the hollow motor 25 of each movable table 10 can be pulled out to the side away from each other, there is an advantage that workability is improved without the other movable table 10 getting in the way during maintenance. is there.

  In the movable table 10 of the above embodiment, the detection means (position detection unit 38) for detecting the rotational position information is integrally incorporated in the hollow motor 25. It may be provided separately from the hollow motor. In this case, for example, as shown in FIGS. 9 (a) and 9 (b), a detecting means 50 is incorporated in the fixed portion 12 and connected to the nut member 16, and the hollow motor 25 is driven and controlled based on the position detection of the nut member 16. (The position detector 38 is not provided in the hollow motor 25 in the configuration shown in the figure). In this case, in particular, as shown in FIG. 9A, if the detecting means 50 is arranged outside the nut member 16 (left side in the figure), the detecting means 50 is pulled out from the movable table 10 at the time of failure. Can be repaired or exchanged, and has the advantage of good maintainability. Of course, a rotary encoder or the like can be used as the detecting means 50 in addition to the resolver.

In the movable table 10 of the above embodiment, the nut member 16 and the hollow motor 25 are arranged in a line in the front-rear direction and are connected to each other by the coupling 20. The nut member 16 may be fixed to each other in a state where a part of the nut member 16 is directly inserted into the inside of 30B, and thereby the hollow motor 25 and the nut member 16 may be directly connected. According to this configuration, since the hollow motor 25 and the nut member 16 overlap in the front-rear direction, the movable table 10 can be made compact in the front-rear direction, and the movable range of the movable table 10 can be expanded accordingly. There is an advantage that becomes possible. However, in this case, since the movable table 10 increases in size in the thickness direction (vertical direction in FIG. 1) due to the overlap portion, in order to reduce the thickness of the single-axis robot, as in the above embodiment. It is preferable that the hollow motor 25 and the nut member 16 are arranged in a line in the front-rear direction.

It is a longitudinal cross-sectional view which shows the structure of the single axis robot used as the base of this invention. It is a principal part top view of the single axis robot which shows the part of a movable table. FIG. 2 is a transverse sectional view of the single-axis robot (a sectional view taken along line AA in FIG. 1). It is a cross-sectional view of a single-axis robot (cross-sectional view taken along line BB in FIG. 1). It is a longitudinal cross-sectional view which shows the detailed structure of the movable table of a single axis robot. It is a longitudinal cross-sectional view of the movable table which shows the state which pulled out the hollow motor. It is a longitudinal cross-sectional view of a single-axis robot showing a state in which the ball screw shaft is shifted in the axial direction and the hollow motor can be taken out. It is a longitudinal cross-sectional view which shows the single axis robot (structure which provided a pair of movable table) based on this invention. It is a longitudinal cross-sectional view which shows the modification of a movable table ((a) (b) shows the structure which connected the position detection means to the nut member).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Casing 10 Movable table 12 Fixed part 121 Mounting surface 16 Nut member 17 Ball nut 18 Nut holder 18a Sleeve 20 Coupling 25 Hollow motor 28 Motor main-body part 30A Stator 30B Rotor 38 Position detection part

Claims (6)

A pair of movable members configured to be capable of mounting various tools and movably mounted on the rail in a line along the rail, and a screw shaft disposed in parallel to the rail and, with a,
Wherein each movable member, the nut member the is screwed attached to the screw shaft and a nut member supported so as to rotate relative to the screw axis, wherein the internal screw shaft is disposed so as to penetrate a hollow motor for rotating the mounted respectively, a single-axis robot each movable member is moved along the rail each by driving the nut member,
The hollow motor has a hollow shaft-like rotor through which the screw shaft passes and a housing that rotatably holds the rotor, and is arranged so as to be aligned in the axial direction of the screw shaft with respect to the nut member. The rotor is detachably connected to the nut member, and the housing is detachably fixed to the movable member. A connection state of the rotor and the nut member and a fixed state of the housing with respect to the movable member are determined. The single-axis robot is configured to allow displacement in a direction away from the nut member and along the screw shaft by being released . The single-axis robot according to claim 1,
The screw shaft is fixed to the shaft support portion with both ends thereof supported by the shaft support portion, and can be slid in the axial direction with respect to the shaft support portion by releasing the fixed state. A single-axis robot characterized by being provided . The single-axis robot according to claim 2 ,
By releasing the fixed state and sliding the screw shaft in the axial direction, the pair of movable members of the pair of movable members are interposed between one of the shaft support portions and the end portion of the screw shaft. A single-axis robot characterized in that a gap is formed so that a hollow motor on one side can be attached and detached . The single-axis robot according to any one of claims 1 to 3,
Each movable member has a configuration in which a nut member is disposed on a side closer to the other movable member in the axial direction of the screw shaft, and the hollow motor is disposed on a far side . The single-axis robot according to claim 2 ,
By releasing the fixed state and sliding the screw shaft in the axial direction, the movable member can be detached and attached between one of the shaft support portions and the end of the screw shaft. axis robot, wherein Rukoto gap is formed to allow. The single-axis robot according to claim 1 ,
Detection means for detecting rotational position information of the hollow motor is assembled to each movable member, and each detection means is opposite to the hollow motor across the nut member in the axial direction of the screw shaft. uniaxial robot characterized that you have connected to the nut member is disposed in the position.

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