JPS6116594B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an industrial robot, and more particularly to an industrial robot of the teaching and reproducing type with easy load feedback, which grasps a workpiece at the tip of an arm system and performs, for example, buffing work. It is used for.

In the following description, the back and forth movement of the workpiece relative to the robot body is referred to as "X movement", and the vertical movement of the workpiece relative to the robot body is referred to as "Z movement".
The rotation of the workpiece about the central axis of the robot body is called "θ (sheeter) movement."

Furthermore, the "state setting" of the workpiece refers to the "position setting" of the workpiece in three-dimensional space, and the "direction setting" of the workpiece with respect to the tool at the set position.
It is a combination of

As mentioned above, the robot of the present invention is applied to buffing work, etc., but no teaching/reproduction type robot has hitherto been found for the purpose of such work.

When a general-purpose robot is applied to buffing work, for example, if the robot has a range of movement sufficient to handle workpieces, the arm will not have sufficient rigidity, causing vibrations during the work, which is inconvenient. In addition, in the case of an articulated robot, if the load torque of a tool such as a buff is to be fed back to the position of the workpiece, it must be performed using two or more axes, which requires complex calculations and is not practical.

It is also possible to use a cylindrical coordinate type robot. In other words, the bracket can be slid up and down (Z movement) on a pole set up on a rotatable (θ movement) board.
This bracket can be slid back and forth (X
An arm is inserted into the main body (moving), and a workpiece gripper is connected to the tip of this arm so that it can swing up and down. However, in this case, since the strength of the arm in the Z direction is not sufficient, the workpiece cannot be pressed against the tool sufficiently. Furthermore, when the arm is moved backward in the X direction, the tail of the arm protrudes behind the main body, so if the entire body moves θ in this state, it may endanger the surroundings.

The purpose of this invention is to provide a space-saving industrial robot that can fine-grained workpiece condition settings according to various conditions of the workpiece and tool, that facilitates feedback of the load torque of the tool. It's about doing.

A further object of the present invention is to provide an industrial robot which has a workpiece handling function and whose arm has sufficiently high rigidity in the direction of pressing the workpiece against the tool and in the direction of rotation of the tool.

That is, the industrial robot of the present invention is constructed by combining a position setting section having main and sub arms and a direction setting section supported by the tip of the main arm and having a work gripper.

The configuration of the position setting section is substantially the same as that of the industrial robot disclosed in Japanese Patent Application No. 57-25624 (Japanese Unexamined Patent Publication No. 58-143977), which is an earlier application filed by the present applicant. That is, a spline shaft driven by an X-movement motor and a screw shaft driven by a Z-movement motor are erected through a base body rotated by a θ-movement control motor, and a first nut is attached to the former. Insert the second and third nuts into the latter, connect the first and second nuts with a gear, connect the main and sub arms to the second and third nuts in an isosceles link shape, and connect the main arm to the second and third nuts in an isosceles link shape. It has a structure in which a direction setting part is supported at the tip.

In the direction setting section, the main shaft held at the tip of the main arm is driven by the α motion control motor, so that the entire direction setting section turns about the central axis in the vertical direction. When the gear case is driven by the β-motion control motor, the work gripper supported on the lower side of the gear case rotates about the central axis in the front-rear direction, and the gripper is driven by the γ-motion control motor. rotates about its own central axis by

As described above, the robot of the present invention sets the state of the work by appropriately combining the three types of position setting and the three types of direction setting according to the conditions of the work and the tool.

The present invention will be explained in more detail below with reference to embodiments shown in the drawings.

As already mentioned, the teaching/reproducing robot of the present invention is composed of a combination of a position setting section 100 and a direction setting section 200.
Since the configuration of the robot 00 is substantially the same as that of the industrial robot of the prior invention described above, only an outline thereof will be described below.

In FIG. 1, a disk-shaped substrate 111 provided at the bottom of the robot body has a gear 112 on its circumferential surface, and this gear 112 has a gear 114 fixed to the output shaft of a θ movement control motor 113. They are meshingly engaged.

A spline shaft 121 and a screw shaft 122 that are parallel to each other and extend vertically are rotatably supported on the substrate 111. The lower end of the spline shaft 121 is connected to an X movement control motor 115, and
The lower ends of 22 are each operatively connected to a control motor 116 for Z movement.

A first nut 123 with a gear 124 is slidably fitted into the upper part of the spline shaft 121. Further, a second nut 125 with a gear 127 that meshes with the gear 124 and a third nut 126 below the second nut 125 are screwed into the upper part of the screw shaft 122, respectively. The first and second nuts 123 and 125 are connected by a first bracket 128, and the third nut 126 supports a second bracket 129.

The main arm 131 has an upper end connected to the first bracket 128 via a bearing point P, extends forward and downward, and has a holder 131a for the direction setting part 200 at its lower end. The lower end of the sub arm 132 connects to the second bracket 129 via the bearing point Q.
The main arm 131 extends forward and upward, and its upper end is connected to the longitudinal center of the main arm 131 via a bearing point R. Therefore, the bearing points P, Q, and R are located at each vertex of the isosceles triangle.

The position setting work will be explained. When the θ movement control motor 113 is driven, the gears 114 and 112
The substrate 111 is rotated about the central axis via. Therefore, the direction setting unit 200 supported by the arms 131 and 132, and by extension the work gripped thereby, moves by θ, that is, rotates around the central axis.

When the X-movement control motor 115 is driven, the spline shaft 121 and the first nut 123 rotate, and this rotation is transmitted through the gears 124 and 127 to the second nut 123.
The signal is transmitted to the nut 125. At this time, the screw shaft 12
2 does not rotate, the second nut 125 moves up and down along the screw shaft 122 together with the first bracket 128. Both arms 131 and 132 have a bearing point P,
Since they are connected by Q and R, as the first bracket 128 moves up and down, the direction setting unit 200 and, by extension, the work gripped by it move in the X direction.
In other words, it moves back and forth. Of course, at this time, the workpiece does not move along a perfect horizontal plane, but strictly speaking, it moves along an arcuate surface extending in the front-rear direction with the bearing point P as the center. However, if the length of the main arm 131 is set long in consideration of the moving distance, there is no problem in practice even if the workpiece is assumed to move along a substantially horizontal plane.

When the Z movement control motor 116 is driven, the screw shaft 122 rotates, and the second and third nuts 12
5 and 126 move up and down along the screw shaft 122 along with the brackets 128 and 129 while maintaining the mutual spacing. Therefore, since the isosceles triangle connecting the bearing points P, Q, and R maintains its original shape, the direction setting unit 200,
Furthermore, the work that is grasped by it is Z
Move, that is, move up and down.

Through the teaching and reproduction described above, the "position" of the workpiece in the three-dimensional space is set. Of course, in actual teaching reproduction, the three sets of motors 113, 115, and 116 are often driven simultaneously to increase the working speed, so the workpiece is
A predetermined "position" is set by performing a compound movement that combines movements.

Next, regarding the work direction setting section 200, the second
This will be explained using figures. However, in the drawings, only the parts essential to the structure of the invention are shown, and bearings, guides, and multi-strengthening members of various parts are omitted.

The entire direction setting section 200 is supported by a holder 131a at the tip of the main arm. That is, the main shaft 202 rotatably supported by the holder 131a extends vertically, is operatively connected to the α motion control motor 201 at its upper end, and fixedly supports the substrate 203 at its lower end. Here, the α movement refers to the rotation of the entire direction setting section about the central axis extending in the vertical direction of the main shaft 202.

A gear case 207 is provided at the lower end of the substrate 203 so as to be rotatable about a central axis extending in the front-rear direction. On the other hand, a β motion control motor 204 is provided behind the upper main shaft 202 of the board 203, and a bevel gear 205 is provided on the output shaft extending downward.
is fixed, and a bevel gear 2 meshingly engages with this.
The shaft of 06 is located on the central axis of the gear case 207.
is fixed to the rear of the Here, the β motion refers to the rotation of the gear case 207 about the central axis.

A gamma motion control motor 208 is provided in front of the upper main shaft 202 of the board 203, and a shaft 211 of a bevel gear 210 rotatably extends through the front surface of the gear case 207 on the output shaft extending below. , fixedly supports a bevel gear 212 inside. A support shaft 214 of the bevel gear 213 that meshes with the bevel gear 213 rotatably penetrates the bottom surface of the gear case 207 and extends downward, and fixedly supports the gripper 215 at its lower end. This grasper 215 corresponds to a human hand, and supports the workpiece W with its fingers.
It is opposed to a tool T such as a buff. However, since a known finger opening/closing mechanism is used, a description of its display will be omitted. Here, the γ movement refers to the rotation of the grasper 215 about the central axis extending in the longitudinal direction through the axis of the gripper 214. This is equivalent to twisting the wrist in human hands.

Next, according to FIGS. 3A to 3D, the direction setting section 200
Let us explain the α, β, and γ movements in . In FIG. 3A, neither control motor is driven. It is, so to speak, a neutral state.

First, α motion will be explained. When the α motion control motor 201 is driven in the state shown in FIG.
15 are rotated in the same direction and at the same angle, and the whole changes to the state shown in FIG. 3B, for example.

Next, β motion will be explained. When the β motion control motor 204 is driven in the state shown in FIG. 3A, the gear case 207 is
rotates about the central axis, and as a result, grasper 2
15 rotate in the same direction and at the same angle, and the whole becomes in the state shown in FIG. 3C, for example. In this example, grasper 21
5 is slightly slanted toward you when viewed from the paper.

Next, γ motion will be explained. When the γ motion control motor 208 is driven in the state shown in FIG. The state shown in Figure D is reached.

As described above, the "direction" of the workpiece relative to the tool is set by teaching and reproducing. Of course, in actual teaching reproduction, the three sets of motors 201, 204, and 208 are often driven simultaneously in order to increase the working speed, so the workpiece performs a compound motion that is a combination of α, β, and γ movements. It is set in a predetermined "direction".

As is clear from the above, when setting the state of a workpiece by the robot of the present invention, (1) back and forth movement with respect to the robot body, that is, X movement; (2) vertical movement with respect to the robot body, that is, Y movement; 3) Rotation about the central axis, i.e. θ movement; (4) Rotation about the central axis, i.e. α movement; (5) Rotation about the central axis, i.e. β movement; (6) Rotation about the central axis. That is, the γ motion is combined. Therefore, in setting the work condition, 6
You get the freedom of the street. Therefore, it is possible to perform very fine-grained state settings depending on the conditions of the workpiece and tool.

The work W whose condition has been set as described above is pressed vertically downward against the head of a tool T, such as a buff, and undergoes a predetermined work. During machining, the brackets 128 and 129 are guided by guides (not shown) and simply move up and down in the Z direction on a straight line. Therefore, it can be easily guided by a highly rigid sliding mechanism.

In addition, the screw shaft 122 drives the work in the pressing direction (Z direction) of the workpiece against the tool, and the spline shaft 121 drives the work tool in the rotation direction (X direction), making it extremely rigid. The structure is difficult due to high vibration and vibration.

Furthermore, the feedback of the tool load torque is
It is very simple because it only needs to be performed for the position in the Z direction. That is, the load on the tool, for example, a buff, is detected by a torque sensor, and the position in the Z direction is corrected with respect to the taught position point so that the detected value maintains the taught value indicated at the time of teaching. All you have to do is provide feedback. This not only allows you to easily teach the position point without worrying about the contact between the tool and the workpiece, but also allows you to always maintain the initially taught load torque even if the tool becomes smaller due to wear. The workpiece is driven in the Z direction as if to protect it.

The robot of the present invention is applicable not only to buffing work but also to sanding work, grinding work, and wrapping work.

[Brief explanation of the drawing]

FIG. 1 is a partially sectional side view schematically showing the position setting section in the structure of the robot of the present invention, FIG. 2 is a partially sectional side view schematically showing the direction setting section in the structure of the robot of the present invention, and FIG. Figures A to D are perspective views illustrating the action of setting the direction of a workpiece by the robot of the present invention. 100... Position setting section, 111... Board, 113...
θ movement control motor, 115...X movement control motor, 116...Z movement control motor, 121
...Spline shaft, 122...Screw shaft, 131...Main arm, 132...Sub-arm, 200...Direction setting section,
201...α motion control motor, 202...main shaft, 2
03... Board, 204... β motion control motor, 20
7...Gear case, 208...γ motion control motor,
215...grasper, W...workpiece, T...tool, ~
...Central axis.

Claims (1)

[Claims] 1. X, Z, θ position setting unit 100 of the workpiece in the three-dimensional space and α, θ of the workpiece with respect to the tool
It consists of a β and γ direction setting section 200, and the position setting section 100 includes a θ movement control motor 1.
A spline shaft 121 and a screw shaft 122 are driven by
Main and sub arms 131 and 132 are connected to two nuts 125 and 126 on a screw shaft rotated by the Z movement control motor 116 in the form of isosceles links, and are splined. The shaft is driven by the X movement control motor 115 to rotate one nut on the screw shaft,
and an α movement control motor 201 in which the direction setting unit 200 supported at the tip of the main arm 131 horizontally rotates the entirety thereof about a central axis in the vertical direction;
It is characterized by having a β movement control motor 204 that rotates the workpiece gripper 215 about a central axis in the front-rear direction, and a γ movement control motor 208 that rotates the gripper about a central axis that points toward its own workpiece. An industrial robot. 2. A substrate 2 on which the direction setting unit 200 is connected to the output shaft of the α motion control motor 201 and supports the β and γ motion control motors 204 and 208.
03, and a gear case 207 is supported on the lower side of the board so as to be rotatable about a central axis in the longitudinal direction, and is operatively connected to the β motion control motor 204 via a bevel gear train. A patent claim characterized in that a work gripper 215 is rotatably supported on the lower side of the gear case about its own central axis, and is operatively connected to a gamma motion control motor 208 via a bevel gear train. The industrial robot according to item 1.