JPS6228129A - Hand device for industrial robot - Google Patents

Abstract

PURPOSE:To enable a rotary tool to damp its rapid change of reaction, by movably inserting a steel ball, which presses a groove by a spring 9 fixed by screwing a plug thread, into a hole provided in a frame. CONSTITUTION:If a rotary tool 13 machines a work by actuating a driving unit 12, a device generates reaction force tending to turn a sliding shaft 5 by machining resistance received by the rotary tool 13. Tension of a spring 9, pressing a steel ball 7 to be brought into contact with the bottom surface of a groove 6, overcomes against said reaction force to suppress turning of the sliding shaft 5. Balance between the spring tension pressing the steel ball 7 and the reaction force of the sliding shaft 5 is determined from the tension of the spring 9 and a value of the reaction force, generated by the rotary tool 13 changing by shape of a curved surface of the groove 6 and a steady condition, in accordance with a respectively preliminary machining condition. While the device, even if reaction force exceeding the steady condition is applied acting on the sliding shaft 5, stops an overrevolution preventing piece 10 in a position before it is brought into contact with an overrevolution preventing wall 3.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a hand device for an industrial robot that performs work such as tightening screws or drilling holes in products on a production line, and particularly relates to a hand device for an industrial robot that performs work such as tightening screws or drilling holes in products on a production line. This invention relates to an industrial robot's end device that is designed to prevent damage to the end device when rotational torque rapidly increases, such as at the start of drilling.

[Conventional technology]

FIGS. 7 and 8 are a plan view and a side view showing an example of a conventional industrial robot device for tightening screws or drilling holes by applying rotation to a workpiece. (1) l'j robot arm, (2) is a frame, CI) has both ends fixed to the frame (2) f' and a pair of shafts, (a) is fitted with a shaft (c) to move it up and down. The sliding support, ■ and (c) are the springs that narrow the support H and apply compressive force from above and below, (6) is the drive unit, and (to) is the rotating tool. Note that the support (A) consists of two axes (2
) so that it is not restrained in the rotational direction with respect to the frame (2).

In the screwdriver having the above-mentioned structure, for example, when tightening a screw onto a workpiece, the robot arm (1) descends and inserts the rotary tool into the bolt of the workpiece while pressing it. The pressing force at this time causes the support (a) to slide upward and perform an axial floating motion, and when the rotary tool (to) is fitted onto the bolt, the drive unit (6) is actuated and the rotary tool α Drive → and tighten the specified screws.

[Problem that the invention seeks to solve]

When performing screw-in work using a conventional screwdriver such as the one mentioned above, for example, a bolt, the reaction force of the rotational torque is instantaneously generated when the screw-in operation, which is performed with a steady value of rotational torque, transitions to the final tightening. The problem is that the impact force is propagated to the frame (2), shaft (c), and robot arm (1), and a dynamic action is added that may cause severe damage was there.

In order to solve this problem, this invention
Even if the rotating tool is suddenly subjected to a reaction force due to rotational torque that exceeds the steady value, the rotating tool will stop within a predetermined rotation angle and this rapidly increasing reaction force can be alleviated.
The purpose is to obtain a standard device.

[Means for solving problems]

The robot arm according to the present invention includes a frame fixed to the tip of the robot arm, and a rotary tool fitted to the tip of the frame, which fits into a through hole formed in the frame in a direction perpendicular to the robot arm. A steel ball is provided in the fitting part of the slide shaft and presses the bottom of a groove with a curved cross section in the axial direction with a spring.During steady turning torque, this steel ball moves against the slide. Press the bottom of the shaft,
When the turning torque rapidly increases, the pressing point of the steel ball moves over the curved surface of the groove in response to the rotation of the slide shaft.

[Effect]

In this invention, the spring force of the steel ball pressing against the bottom of the slide groove overcomes the reaction force of the rotary tool at the tip of the slide shaft against a predetermined steady-state turning torque, causing the slide shaft to rotate. When the turning torque rapidly increases, the reaction force due to this rapidly increased turning torque overcomes the spring force pressing the steel ball, causing the slide shaft to rotate.

〔Example〕

FIG. 1 is a partial sectional view of a hand device according to an embodiment of the present invention, FIG. 2 is a top view of FIG. 1, and FIG. 3 is the same <A-A
This is a cut-away view. (1) is a robot arm, (2) is a frame fixed to the tip of robot arm (1), (
3) FL specific rotation shield piece provided on the ll-j frame (2), (5) is a slide shaft that fits into a hole provided in the frame (2) and can move in the axial direction, (6) is a slide A groove (7) with a curved cross section provided on the shaft is loosely fitted into a hole provided in the frame (2), and fixed by screwing the plug screw (8) into the groove (6). ), 01 is the over-rotation prevention +h piece fixed to the end of the slide shaft (5), C11) is the compression spring that presses down the slide shaft (5), (6) is fixed to the slide shaft The drive unit (to) is a rotary tool such as a screw spanner or a drill that rotates by the operation of the drive unit ◇→.

In the cutting device according to the present invention configured as described above, the rotary tool (to) performs screw tightening, drilling, etc. on the broken workpiece by the operation □ of the drive unit (6), and each As shown in Figs. 1 and 6, the steel ball ( 7) is overcome by the spring force of the spring (9) that presses against the bottom surface of the groove (6), suppressing the rotation of the slide shaft (5).

For example, at the end of screw tightening, the rotating ball A (13
The reaction force of the slide @ (5) suddenly increases from the steady state, and this reaction force overcomes the spring force that is fully pressing the groove (6) by the steel ball (7), and the slide shaft (5) rotates, and the point of contact between the steel ball (7) and the groove (6) moves as shown in Figures 4 and 6, and the spring (9) is compressed and presses the steel ball (7). When the spring force increases and the increased spring force and the rapidly increased reaction force against the slide shaft (5) are balanced, the rotation of the slide shaft (5) is stopped. The balance between the spring force pressing the steel ball (7) and the reaction force of the slide shaft (5) is determined by the strength of the spring (9) and the groove (6).
) and the shape of the curved surface of the rotating tool (
It is determined in advance according to each machining condition from the value of the machining reaction force caused by (to). For example, in the case of screw tightening as described above, the curved surface of VC is determined by calculating the shape of the spring (9) and the strength of the spring (9).

In addition, in normal operation, the slide axis (5)
Even if a reaction force exceeding the steady state is applied to the over-rotation prevention wall (3), the over-rotation prevention piece αq will stop at a position where it does not come into contact with the over-rotation prevention wall (3) in balance with the spring force, as shown in Figure 5, but an abnormality will occur. By applying these conditions, even if the slide shaft (5) rotates more than a predetermined amount, the over-rotation prevention piece αq will prevent the over-rotation prevention wall (
3) and is cut off, and the slide shaft (5) rotates, so there is no risk that the robot arm (1) etc. will be damaged due to the generation of abnormal reaction force.

〔Effect of the invention〕

As explained above, this invention is configured so that when a reaction force exceeding a steady value is generated on the rotary tool, this reaction force and a pre-calculated spring force are balanced and the rotation of the slide shaft is stopped at a predetermined angle. Therefore, it is possible to obtain a robot hand that can buffer sudden changes in the reaction force of the rotary tool.

[Brief explanation of the drawing]

FIG. 1 is a partial sectional view of a robot hand device according to an embodiment of the present invention, FIG. 2 is a top view of FIG. 1, and FIG. 3 is the same <
4 is a partial sectional view for explaining the invention in detail, FIG. 5 is a top view of FIG. 4, and FIG. 6 is the same (A-A sectional view, FIG. 8 is a plan view showing an example of a conventional robot hand device equipped with a rotary tool, and FIG. 8 is a side view thereof. In the figure, (1) the V! robot arm, (2) the frame, and (5) the slide. The shaft, (6) is the groove, (7) is the steel ball, (9) is the spring, and (to) is the rotary tool. Note that the same reference numerals in the drawings indicate the same or equivalent parts. Agent: Masatoshi Sato, patent attorney Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 7 Cause Figure 8 12+3 21

Claims (1)

[Claims] A frame fixed to the tip of the robot arm, a slide shaft that fits into a through hole provided in this frame and has a rotary tool at its tip, and a shaft that fits into the through hole of this slide shaft. A steel ball is provided that presses a groove with a curved cross section provided in the direction by a spring force, and in a steady state, the spring force overcomes the reaction force due to the rotational torque of the rotary tool, and the steel ball presses the groove in the groove. An industrial robot characterized in that when the bottom surface is pressed and a reaction force exceeding a steady value is applied, the slide shaft rotates and the pressing point of the steel ball moves along the curved surface of the groove. hand device.