JPH05169333A - Work pressing mechanism - Google Patents

Abstract

PURPOSE:To surely press plural kinds of works having similar form by providing assembling means such as a screw fastening hand attached to a robot through a shaft so as to be vertically movable and rotatable with pressing means to elastically press the work. CONSTITUTION:A pressing element 26 is provided on a screw fastening hand 11 functioning as assembling means attached to a robot through a shaft 5 so as to be vertically movable and rotatable. A position where works 31, 32 are pressed by the pressing element 26 through the rotation of the shaft 5 can therefore be voluntarily set up within a fixed range. Thus a position where the works 31, 32 can be surely pressed by the pressing element 26 can be selected to make highly reliable assembling work practicable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work holding mechanism for pressing and fixing a work in a screw tightening process or the like provided in an automatic assembly line.

[0002]

2. Description of the Related Art In an automatic assembly line, for example, when a screw tightening hand unit attached to a robot is used for screw tightening a work, conventionally, the screw tightening is performed without holding the work or a screw tightening hand unit different from the screw tightening hand unit is used. A dedicated work holding device was provided to press and fix the work. Alternatively, a pressing mechanism adapted to the shape of the work is fixedly provided around the screw tightening hand unit.

[0003]

However, when the screw tightening is performed without pressing the work, there is a drawback that the screw tightening failure is likely to occur. Further, if a dedicated work holding device is provided, the space is required and the cost is increased. Furthermore, when a pressing mechanism that matches the shape of the work is provided around the screw tightening hand unit, the work cannot be pressed completely when the shape of the work changes because the pressing position is fixed, and the screw is tightened to the tightening position. There was a fear that there was no. In particular, when an elastic material such as a spring or rubber is installed between the work to be tightened and the screw is tightened, a force is generated in the direction opposite to the direction in which the screw is fixed, making reliable screw tightening difficult. was there.

The present invention has been made in view of the above circumstances, and has a simple structure capable of reliably pressing a plurality of types of works having similar shapes and performing highly reliable assembly. An object is to provide a work holding mechanism having general versatility.

[0005]

A work pressing mechanism according to a first aspect of the present invention is attached to a shaft provided on the robot 100 so as to be vertically movable and rotatable, and serves as an assembling means for assembling the works 31 and 32. Work 3 for the screw tightening hand
Pressing element 2 as pressing means for elastically pressing 1, 32
6 is provided.

The work holding mechanism according to the second aspect is characterized in that the assembling means is the screw tightening hand 11 as the screw tightening means.

[0007]

In the work holding mechanism according to the first aspect,
The screw tightening hand 11 is an assembling means in which the presser 26 is attached to the robot so as to be vertically movable and rotatable via the shaft 5.
Since it is provided, it is possible to arbitrarily set the position where the pressing element 26 presses the works 31, 32 by rotating the shaft 5 within a predetermined range. Therefore, it is possible to select a position where the pressers 26 can reliably press the works 31, 32, and a highly reliable assembly operation can be performed.

In the work holding mechanism according to the second aspect, the screw tightening hand 11 can perform the screw tightening work with high reliability.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the work holding mechanism of the present invention will be described below with reference to the drawings.

1 and 2 show the configuration of an embodiment of the present invention. FIG. 2 shows an example of a robot equipped with a screw tightening hand provided with a work holding mechanism according to this embodiment. This robot 100 is a low dust generation type robot that has been subjected to a dustproof treatment, which is particularly used in a clean room.
In FIG. 2, one end of a first arm 2 is attached to a base 1 so as to be horizontally rotatable.
One end of the second arm 3 is rotatably attached to the other end of the. A Z-axis 4 is provided at the other end of the second arm 3 so as to be vertically movable, and an R-axis 5 is concentrically attached to the Z-axis 4 so as to be rotatable. The first arm 2, the second arm 3 and the R-axis 5 are rotated by the DC servomotors 6, 7, 8 respectively, and the Z-axis 4 is vertically moved by the DC servomotor 9. Each of these servomotors 6 to 9 is driven by a software servo.

A screw tightening hand 11 shown in FIG. 1 is attached to the Z axis 4 and the R axis 5 of the robot 100. The motor 13 is housed in the upper part of the housing 12 of the screw tightening hand 11, and the motor 1 is installed in the lower part of the motor 13.
A deceleration mechanism portion 14 for decelerating the rotation of No. 3 is provided.
A closed cylindrical base frame 15 forming a vacuum chamber for adsorbing a screw described later is attached to the lower portion of the speed reduction mechanism portion 14. A suction pipe 16 connected to a vacuum source is attached to the base frame 15.

A pit holder 17 is fixed to the output shaft of the reduction mechanism 14 concentrically with the base frame 15. A rotary pit 18 is locked in the pit holder 17 for rotation and is mounted so as to be slidable in the axial direction. Has been done. Further, a lip 19 is concentrically provided inside the lower end of the base frame 15 so as to be freely rotated in the rotation pit 18 so as to be rotatable, and between the lip 19 and the inner periphery of the base frame 15. Lip floating spring 20
Is installed. Further, a cap 21 is screwed on the lower end surface of the base frame 15 to regulate the descending end of the lip 19. The position of the cap 21 is adjusted by an adjusting ring 22 screwed on the outer periphery of the base frame 15. Further, the rotary pit 18 penetrates the center of the cap 21 and projects downward, and the inside of the base frame 15 communicates with a through hole (not shown) which penetrates the center of the rotary pit 18. Then, the inside of the base frame 15 is evacuated via the suction pipe 16, so that the screw 23 is sucked onto the tip of the rotary pit 18.

On the other hand, a bracket 24 is provided on the outer periphery of the base frame 15.
Is fixed, and the rotating pit 18 is attached to the bracket 24.
A support shaft 25 is provided so as to be movable in a direction parallel to. The lower end of the support shaft 25 has a pusher 2 as a pressing means.
6 is attached, and the pressing element 26 is pressed and biased in the direction indicated by the arrow A by the compression coil spring 27.

Next, an operation procedure for performing the screw tightening work according to this embodiment will be described. As shown in FIGS. 3 and 4, the first
The work 31 and the second work 32 are combined and mounted by aligning the positions of the mounting hole 31a and the screw hole 32a, respectively. On the other hand, the first arm 2 and the second arm 3 of the robot shown in FIG. 2 are rotated, and the screw 23 attracted to the tip of the rotary bit 18 is positioned right above the mounting hole 31a. At the same time, the R shaft 5 is rotated to move the presser 26 in a circle indicated by an arrow B, and the presser 26 selects and presses the work 31 and 32. Then, while the lower surface of the pressing element 26 presses the upper surface of the first work 31 by the urging force of the compression coil spring 27, the rotation pit 18 is rotated by the motor 13 and the Z axis 4 is lowered to attach the screw 33 to the mounting hole 31a and the mounting hole 31a. It is inserted into the screw hole 32a and screwed.

When the screw tightening is completed and the torque-up signal is issued, the rotation of the motor 13 is stopped and the Z-axis 4 is raised,
At the same time, the presser 26 is also separated from the upper surface of the first work 31 to complete the screw tightening work.

According to the present embodiment, even if the height of the upper surface of the first work 31 changes, the pressing element 26 is not compressed by the compression coil spring 2.
Since the workpieces 31 and 32 are pressed by the biasing force of 5, the screws 31 can be prevented from floating and a highly reliable screw tightening operation can be performed. Further, if the shapes of the works 31 and 32 are relatively similar to each other, the R-axis is rotated to move the pressing element 26 to a position where the works 31 and 32 can be pressed most effectively, thereby tightening screws of different works. Can be reliably performed. In this case, the rotation angle of the R-axis 5 corresponding to the work is taught to the robot in advance, and the R-axis 5 is rotated by the software program, whereby the pressing member 26 can be positioned in a short time.

FIG. 5 shows the mounting seat 41a of the mold base 41.
The case where the coil spring 42 is mounted on the outer periphery of the shaft and the shaft 44 mounted on the mold lever 43 is press-fitted in the center of the mounting seat. In this case, the screw tightening hand 11 has a rotating bit 18
Instead, the press-fitting chuck 45 may be attached and the Z-axis 4 may be lowered. In this case as well, the mold lever 43 is moved to the presser 4
By pressing the mold base 41 at 6, reliable assembly can be performed.

In FIG. 6, an elastic material 53 such as a gasket is inserted between a pair of sheet metal drawing works 51 and 52, and a rivet 54 is used.
Shows the case of caulking. In this case, screw tightening hand 1
By mounting the rivet crimping punch 55 on 1 and crimping the rivet 54 while pressing the works 51 and 52 with the presser 56, reliable assembly can be performed.

Not only the assembling work shown in each of the above embodiments,
By attaching the work holding mechanism of the present invention to the assembly work hand when assembling components from above while fixing the work, highly reliable assembly can be performed.

[0020]

As described above, according to the work holding mechanism of the present invention, the work is elastically attached to the assembling means such as the screw tightening hand attached to the robot so as to be vertically movable and rotatable via the shaft. Since the pressing means for pressing the
It is possible to select the position where the pressing means presses the work, and it is possible to reliably press a plurality of types of works having similar shapes. Therefore, highly reliable assembly work can be performed.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view showing a configuration of a screw tightening hand provided with an embodiment of a work holding mechanism of the present invention.

FIG. 2 is a front view showing an example of a robot to which the screw tightening hand shown in FIG. 1 is attached.

FIG. 3 is a plan view showing an example of the shape of a work screwed by the screw tightening hand shown in FIG.

4 is a vertical cross-sectional view of FIG.

FIG. 5 is an explanatory view showing another example of the work assembling work.

FIG. 6 is an explanatory view showing another example of the work assembling work.

[Explanation of symbols]

 4 Z-axis (axis) 5 R-axis (axis) 11 Screw tightening hand (assembly means) 26 Pusher (pressing means) 31, 32 Work 100 Robot

Claims (2)

[Claims] 1. A work, characterized in that a pressing means for elastically pressing the work is provided in an assembling means for assembling the work, which is attached to a shaft that is vertically movable and rotatable in the robot. Presser mechanism. 2. The work holding mechanism according to claim 1, wherein the assembling means is a screw tightening means.