JP7602008B2 - robot - Google Patents

Description

This specification discloses a robot.

Conventionally, a robot arm equipped with a force sensor has been proposed (see, for example, Patent Document 1).

Special table number 2019-504680

When attaching a force sensor to a robot arm so as to be interposed between the load section (end effector) and the drive motor, depending on the arrangement of the bearing member and the load section, there is a risk that an unintended force will be detected by the force sensor due to interference between the inner ring of the bearing member and the load section.

The primary objective of this disclosure is to prevent the force sensor from detecting unintended forces due to interference between the inner ring of the bearing member and the load portion.

This disclosure takes the following measures to achieve the above-mentioned primary objective.

The robot of the present disclosure is
A robot arm;
A drive motor fixed to the robot arm;
An outer ring of a bearing member fixed to the robot arm;
an inner ring of the bearing member that rotates along the outer ring;
a support portion for a force sensor fixed to the inner ring and rotated by the drive motor;
an action portion of the force sensor supported by the support portion;
A load portion connected to the action portion and inserted through the inner ring;
The gist of the invention is to provide the following:

In the robot disclosed herein, the support part of the force sensor, which is rotated by the drive motor, is fixed to the inner ring of the bearing member, and the load part is inserted through the inner ring of the bearing member to connect the action part of the force sensor. This makes it possible to prevent the force sensor from detecting unintended forces due to interference between the inner ring of the bearing member and the load part.

FIG. 1 is an external perspective view of a robot according to an embodiment of the present invention. FIG. FIG. 2 is a schematic diagram of a tip portion of the robot. FIG. 2 is a cross-sectional view of the tip of the robot. FIG. 2 is a schematic diagram of a force sensor. FIG. 13 is a schematic configuration diagram of a robot tip portion according to another embodiment.

Next, a form for implementing the present disclosure will be described with reference to the drawings. Fig. 1 is an external oblique view of the robot. Fig. 2 is a side view of the robot body. Fig. 3 is a schematic diagram of the robot tip. Fig. 4 is a cross-sectional view of the robot tip. In Fig. 1, the left-right direction is the X-axis, the front-back direction is the Y-axis, and the up-down direction is the Z-axis.

As shown in Figures 1 to 3, the robot 10 of this embodiment comprises a robot body 20 and a force sensor 70.

2, the robot body 20 includes a first arm 21, a second arm 22, a base 25, a base 26, a first arm drive motor 35, a second arm drive motor 36, a posture holding device 37, a lifting device 40, and a three-axis rotating mechanism 50. The first arm 21, the second arm 22, and the three-axis rotating mechanism 50 may be simply referred to as arms.

The base end of the first arm 21 is connected to the base 25 via a first joint shaft 31 extending in the vertical direction (Z-axis direction). The rotation shaft of the first arm drive motor 35 is connected to the first joint shaft 31. The first arm drive motor 35 rotates (pivots) the first arm 21 along a horizontal plane (XY plane) with the first joint shaft 31 as a fulcrum.

The base end of the second arm 22 is connected to the tip end of the first arm 21 via a second joint shaft 32 extending in the vertical direction (Z-axis direction). The rotation shaft of the second arm drive motor 36 is connected to the second joint shaft 32. The second arm drive motor 36 rotates the second joint shaft 32, thereby rotating (pivoting) the second arm 22 along a horizontal plane with the second joint shaft 32 as a fulcrum.

The base 25 is provided so as to be movable up and down with respect to the base 26 by a lifting device 40 installed on the base 26. As shown in Figs. 1 and 2, the lifting device 40 includes a slider 41 fixed to the base 25, a guide member 42 fixed to the base 26 and extending in the vertical direction to guide the movement of the slider 41, a ball screw shaft 43 (lifting shaft) extending in the vertical direction and screwed into a ball screw nut (not shown) fixed to the slider 41, and a lifting drive motor 44 that rotates the ball screw shaft 43. The lifting device 40 moves the base 25 fixed to the slider 41 up and down along the guide member 42 by rotating the ball screw shaft 43 with the lifting drive motor 44.

The three-axis rotating mechanism 50 is connected to the tip of the second arm 22 via the attitude-maintaining shaft 33 extending in the vertical direction. The three-axis rotating mechanism 50 includes a first rotating shaft 51, a second rotating shaft 52, and a third rotating shaft (tip shaft 53) that are perpendicular to each other, a first rotating shaft drive motor 55 that rotates the first rotating shaft 51, a second rotating shaft drive motor 56 that rotates the second rotating shaft 52, and a tip shaft drive device 60 that drives the tip shaft 53. The first rotating shaft 51 is supported in an orthogonal attitude with respect to the attitude-maintaining shaft 33. The second rotating shaft 52 is supported in an orthogonal attitude with respect to the first rotating shaft 51. The third rotating shaft (tip shaft 53) is supported in an orthogonal attitude with respect to the second rotating shaft 52. The tip shaft 53 holds an end effector EF as a load section so as to be coaxial with the tip shaft 53a.

In this embodiment, the robot body 20 can move the tip axis 53, i.e., the end effector EF, to any position in any attitude by combining translational motion in three directions, the X-axis direction, the Y-axis direction, and the Z-axis direction, by the first arm drive motor 35, the second arm drive motor 36, and the lifting device 40, with rotational motion in three directions, around the X-axis (pitching), around the Y-axis (rolling), and around the Z-axis (yawing), by the rotating three-axis mechanism 50.

The attitude holding device 37 holds the attitude of the three-axis rotating mechanism 50 (the orientation of the first rotating shaft 51) in a constant orientation regardless of the attitudes of the first arm 21 and the second arm 22. The attitude holding device 37 controls the rotation angle of the attitude holding shaft 33 based on the rotation angle of the first joint shaft 31 and the rotation angle of the second joint shaft 32 so that the axial direction of the first rotating shaft 51 is always in the left-right direction (X-axis direction). This makes it possible to control the translational motion in three directions and the rotational motion in three directions independently, making control easier.

As shown in Figures 2 to 4, the tip shaft drive device 60 comprises a frame 61, a drive motor 62, a power transmission mechanism 63, a connecting shaft 65, a bearing member 67, a gripping member 69 and a force sensor 70.

The frame 61 is a rectangular frame fixed to the second rotating shaft 52, and rotates integrally with the second rotating shaft 52 when driven by the second rotating shaft 52. The drive motor 62 is fixed to the frame 61 so that its rotating shaft 62a is parallel to the axial direction of the second rotating shaft 52. The connecting shaft 65 is supported by the frame 61 so as to extend in the vertical direction. In other words, the connecting shaft 65 extends in a direction perpendicular to the rotating shaft 62a of the drive motor 62 and the second rotating shaft 52.

The power transmission mechanism 63 has a bevel gear 63a attached to the rotating shaft 62a of the drive motor 62 and a bevel gear 63b attached to the connecting shaft 65 and meshing with the bevel gear 63a. The power transmission mechanism 63 connects the rotating shaft 62a of the drive motor 62 and the connecting shaft 65, which are perpendicular to each other, to transmit the power from the drive motor 62 to the connecting shaft 65.

The force sensor 70 detects the force components acting in the axial directions of the X-axis, Y-axis, and Z-axis as external forces, and the torque components acting around each axis. As shown in FIG. 5, the force sensor 70 has an action part 71 on which a force acts, an annular support part 72 that supports the action part 71 on the inner circumferential side, and a detection part 73 that is arranged at a predetermined interval in the circumferential direction between the action part 71 and the support part 72 and detects the force acting on the action part 71. As shown in FIG. 4, the upper surface of the support part 72 is superimposed on and connected to the lower surface of the flange part 65a formed at the lower end of the connecting shaft 65. In addition, the lower surface of the support part 72 is superimposed on and connected to the upper surface of the flange part 66a formed at the upper end of the cylindrical fixing member 66. The cylindrical outer peripheral surface of the fixing member 66 is fixed to the inner peripheral surface of the inner ring 67a of the bearing member 67. That is, the support part 72 is fixed to the inner ring 67a of the bearing member 67 via the fixing member 66. An outer ring 67b of the bearing member 67 is fixed to the frame 61. As a result, the connecting shaft 65 and the support portion 72 of the force sensor 70 are rotatably supported by the frame 61 via the bearing member 67.

The lower surface of the action part 71 is connected to the upper end of the tip shaft 53, and the end effector EF is attached to the lower end of the tip shaft 53 via a retaining part (not shown). Furthermore, the base end of the gripping member 69 is connected to the upper surface of the action part 71 as a second load part. The gripping member 69 is provided so as to extend in the outer diameter direction relative to the connecting shaft 65. Thus, in this embodiment, the end effector EF is connected to the lower surface of the action part 71 of the force sensor 70 via the tip shaft 53, and the gripping member 69 is directly connected to the upper surface of the action part 71, so that forces act on the action part 71 from both the upper and lower surfaces. This allows the force received from the end effector EF and the force received from the gripping member 69 to be detected by a single force sensor 70.

As shown in FIG. 4, the tip shaft 53 is inserted into the inner ring 67a of the bearing member 67. In this embodiment, the cylindrical outer peripheral surface of the fixing member 66 connected to the support portion 72 of the force sensor 70 is fixed to the inner peripheral surface of the inner ring 67a, and the tip shaft 53 is inserted into the inner circumference of the fixing member 66. As shown in FIG. 4, a predetermined radial gap is provided between the cylindrical inner peripheral surface of the fixing member 66 and the outer peripheral surface of the tip shaft 53. This prevents the tip shaft 53 connected to the action portion 71 of the force sensor 70 and the fixing member 66 (inner ring 67a) fixed to the support portion 72 of the force sensor 70 from interfering with each other, thereby preventing the force sensor 70 from detecting an unintended force due to interference.

In addition, by interposing a power transmission mechanism 63 between the rotating shaft 62a of the drive motor 62 and the tip shaft 53, the end effector EF can be attached coaxially with the tip shaft 53 while the rotating shaft 62a of the drive motor 62 is arranged on an axis different from the tip shaft 53. This allows the shaft length to be shortened compared to when the rotating shaft 62a of the drive motor 62, the tip shaft 53, and the end effector EF are arranged coaxially.

Furthermore, a gripping member 69 is connected to the upper surface of the action portion 71 of the force sensor 70. Therefore, when performing direct teaching in which the operator manually moves the robot body 20 to record the operation of the robot body 20, the operator can grip the gripping member 69 and move the arm directly, making operation easier. In addition, at this time, the force sensor 70 can detect the external force applied from the gripping member 69, so the operation of the robot body 20 can be recorded more accurately. Of course, direct teaching can also be performed by gripping the end effector EF and moving the robot body 20. In this case, the gripping member 69 may be omitted.

Here, the correspondence between the main elements of the embodiment and the main elements of the present disclosure described in the claims will be described. That is, the first arm 21, the second arm 22, and the three-axis rotating mechanism 50 of this embodiment correspond to the robot arm of the present disclosure, the inner ring 67a of the bearing member 67 corresponds to the inner ring of the bearing member, the outer ring 67b of the bearing member 67 corresponds to the outer ring of the bearing member, the support part 72 of the force sensor 70 corresponds to the support part of the force sensor, the action part 71 of the force sensor 70 corresponds to the action part of the force sensor, and the tip shaft 53 and the end effector EF correspond to the load part. Also, the gripping member 69 corresponds to the second load part. Also, the connecting shaft 65 corresponds to the connecting member, the frame 61 corresponds to the frame, and the power transmission mechanism 63 corresponds to the power transmission member. Also, the bevel gears 63a and 63b correspond to the bevel gears.

It goes without saying that the present disclosure is in no way limited to the above-described embodiments, and may be implemented in various forms as long as they fall within the technical scope of the present disclosure.

For example, in the above-described embodiment, the tip shaft driving device 60 includes a driving motor 62 arranged so that the rotating shaft 62a is perpendicular to the connecting shaft 65 that is coaxial with the tip shaft 53, and a power transmission mechanism 63 that connects the mutually perpendicular rotating shaft 62a and the connecting shaft 65 by bevel gears 63a, 63a to transmit the power from the driving motor 62 to the connecting shaft 65. In contrast, as shown in FIG. 6, a tip shaft driving device 160 according to another embodiment may include a driving motor 162 arranged so that the rotating shaft 162a is parallel to the connecting shaft 165, and a power transmission mechanism 163 that connects the mutually parallel rotating shaft 162 and the connecting shaft 165 by a belt 163a to transmit the power from the driving motor 162 to the connecting shaft 165.

In addition, in the above-described embodiment, the tip axis drive device 60 has a load portion connected to both the upper and lower surfaces of the action portion 71 of the force sensor 70, but the load portion may be connected to only one of the surfaces.

In the above-described embodiment, the robot 10 is configured as a seven-axis articulated robot capable of translational motion in three directions and rotational motion in three directions. However, the number of axes may be any number. The robot 10 may also be configured as a so-called vertical articulated robot or horizontal articulated robot.

As described above, in the robot disclosed herein, the support part of the force sensor rotated by the drive motor is fixed to the inner ring of the bearing member, and the load part is inserted through the inner ring of the bearing member to connect the action part of the force sensor. This makes it possible to prevent the force sensor from detecting unintended forces due to interference between the inner ring of the bearing member and the load part.

In addition, the robot of the present disclosure may include a second load part connected to the surface of the action part opposite to the surface to which the load part is connected. In this way, the force sensor can detect the forces applied from the load part and the second load part.

Furthermore, in the robot of the present disclosure, a connecting member is provided that connects the rotating shaft of the drive motor and the support part, the force sensor has an annular support part that supports the action part on the inner periphery side to which the force acts, the outer ring is fixed to the frame of the robot arm, and the connecting member is connected to the rotating shaft of the drive motor via a power transmission member and is connected to the support part so as to rotate coaxially with the load part by the power from the drive motor. By providing a connecting member and connecting the rotating shaft of the drive motor to the connecting member via a power transmission member, it is possible to ensure the freedom of arrangement of the drive motor and the force sensor while arranging the rotating shaft of the connecting member (the drive shaft of the robot) coaxially with the load part. As a result, it is possible to shorten the shaft length and make the device (tip drive device) more compact.

In a case where a connecting member and a rotating shaft of a drive motor are connected via a power transmission member, the power transmission member may be a bevel gear, and the rotating shaft of the drive motor may be arranged perpendicular to the axial direction of the connecting member and connected to the connecting member via the bevel gear. Alternatively, the power transmission member may be a belt, and the rotating shaft of the drive motor may be arranged parallel to the axial direction of the connecting member and connected to the connecting member via the belt.

This disclosure can be used in the robot manufacturing industry, etc.

10 robot, 20 robot body, 21 first arm, 22 second arm, 25 base, 26 base, 31 first joint shaft, 32 second joint shaft, 33 attitude holding shaft, 35 first arm drive motor, 36 second arm drive motor, 37 attitude holding device, 40 lifting device, 41 slider, 42 guide member, 43 ball screw shaft, 44 lifting drive motor, 50 three-axis rotating mechanism, 51 first rotating shaft, 52 second rotating shaft, 53 third rotating shaft (tip shaft), 55 first rotating shaft drive motor, 56 second rotating shaft drive motor, 60, 160 tip shaft drive device, 61, 161 frame, 62, 162 drive motor, 62a, 162a rotating shaft, 63, 163 power transmission mechanism, 63a, 63b bevel gear, 65, 165 connecting shaft, 66 Fixed member, 66a flange portion, 67 bearing member, 67a inner ring, 67b outer ring, 69 gripping member, 163a belt, 70 force sensor, 71 action portion, 72 support portion, 73 detection portion, EF end effector.

Claims (5)

A robot arm;
A drive motor fixed to the robot arm;
An outer ring of a bearing member fixed to the robot arm;
an inner ring of the bearing member that rotates along the outer ring;
a support portion for a force sensor fixed to the inner ring and rotated by the drive motor;
an action portion of the force sensor supported by the support portion;
a load portion connected to the action portion and to a tip shaft inserted so as not to interfere with the inner ring;
A robot comprising: The robot according to claim 1 ,
A second load portion is provided which is connected to a surface of the action portion opposite to a surface to which the tip shaft is connected.
robot. The robot according to claim 1 or 2,
a connecting member that connects a rotation shaft of the drive motor and the support portion,
the force sensor has an annular support portion that supports, on an inner circumferential side, the action portion on which a force is applied;
The outer ring is fixed to a frame of the robot arm,
The connecting member is connected to a rotating shaft of the drive motor via a power transmission member, and is connected to the support portion so as to rotate coaxially with the tip shaft by power from the drive motor.
robot. The robot according to claim 3,
the power transmission member is a bevel gear,
The rotation shaft of the drive motor is disposed perpendicular to the axial direction of the connecting member and is connected to the connecting member via the bevel gear.
robot. The robot according to claim 3,
the power transmission member is a belt,
The rotation shaft of the drive motor is disposed in parallel with the axial direction of the connecting member and is connected to the connecting member via the belt.
robot.

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