JPH1034448A - Screw fastening device - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To achieve compactness and to be applicable to not only vertical but also horizontal screw tightening. SOLUTION: A screw tightening robot main body 1 comprises a screw tightening head 2, a fixing flange 3 which supports the screw tightening head 2 and is mounted on mounting stays 32, 33, and a connector box 4 which is connected to a controller. I do. Attachment portions 34 are provided on three faces of the front, back and lower faces of the fixing flange 3. When performing the screw tightening operation in the vertical direction, the fixing flange 3 is mounted on the mounting stay 32 at the mounting portion 34 on the front surface of the fixing flange 3. When performing the screw tightening operation in the lateral direction, the fixing flange 3 is attached to the attachment stay 33 at the attachment portion 34 on the lower surface of the fixing flange 3. The direction in which the connection cable 38 is led out of the connector box 4 is
The fixing flange 3 is provided so as to be changeable between a right side direction, a front side direction, and a rear side direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a screw tightening device capable of selecting a mounting direction of a screw tightening head.

[0002]

For example, as an apparatus for automatically performing screw tightening in an assembly line of various devices, the present applicant has manufactured a scalar (horizontal articulated) four-axis screw tightening robot. Is becoming In this apparatus, a first arm that pivots in a horizontal direction with respect to a base is provided.
A second arm that pivots in the horizontal direction with respect to the arm is provided, and a screw head is provided at the tip of the second arm. The screw tightening head is configured to include a rotation mechanism for rotating the screw tightening bit about an axis and an advance / retreat moving mechanism for moving the screw tightening bit up and down in the axial direction (Z-axis direction).

Such a screw tightening robot can perform a screw tightening operation by moving a screw tightening head to an arbitrary position in the horizontal direction, and can cope with various kinds of screws, and has high screw tightening accuracy and high screw tightening accuracy. It has received high praise in that few defects occur.

However, in the above screw tightening robot,
For consumers, the quality may be excessive, and a more compact and relatively inexpensive screw fastening device may be required, for example, a large installation space is required for turning. Also, depending on the assembly equipment,
There was also a demand for screw tightening in the horizontal direction, and the above screw tightening robot was not applicable to the use in the horizontal direction, for example, if the robot was set in the horizontal direction, it could not support the weight of the arm itself and could not operate. .

[0005] A single-screw screwing machine is provided as a compact and inexpensive screw-tightening device. However, this kind of single-screw screwing machine simply requires a fixed tool (driver bit). It rotates at a constant speed while applying the presser force, and does not control the rotational speed or the presser force.Therefore, there are many defects during screw tightening, and it is not applicable to automatic assembly lines etc. Was something.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a screw tightening device which can be made compact and can be applied not only to a vertical screw but also to a horizontal screw. To offer.

[0007]

According to a first aspect of the present invention, there is provided a screw tightening device for rotating a screw tightening bit about an axis, and moving the screw tightening bit forward and backward in the axial direction. A screw head having a mechanism, a fixing flange that supports the screw head and is attached to a mounting stay, and a connector provided on the fixing flange for connecting the screw head to a controller And a box,
The fixing flange has a plurality of mounting portions, and is selectively mounted on the mounting stay at any one of the mounting portions, so that the axial direction of the screwing head portion is used as a vertical direction or a horizontal direction. It has features where it is possible.

[0010] According to this, a plurality of mounting portions provided on the fixing flange can take several mounting forms with respect to the mounting stay. Can be used. In this case, one kind of fixing flange can be shared for various mounting forms. Further, since the screw tightening head is directly attached to the mounting stay via the fixing flange, it is possible to achieve a sufficient space saving as compared with the case where an arm or the like is present, and to reduce the space in the lateral direction. In this case, it can easily support its own weight. As a result, according to the screw tightening device of the present invention, it is possible to reduce the size and to apply the screw tightening not only vertically but also horizontally.

Further, in the above screw tightening device, the connector box can be provided so that the mounting direction can be changed with respect to the fixing flange (the invention of claim 2). According to this, the lead-out direction of the wiring in the connector box can be changed arbitrarily. For example, depending on the use position of the mounting portion of the fixing flange and the environment in which the device is installed, the connector can be installed in a direction most advantageous in terms of space. By arranging the boxes, it is possible to further save space.

[0010] Furthermore, the controller is configured to sequentially execute four steps of engagement, screwing, tightening, and torque holding at a predetermined bit rotation speed and a predetermined screw holding force when executing a screw tightening operation. It is also possible to adopt a configuration for controlling the screw tightening head (the invention of claim 3). According to this, precise control suitable for the screw tightening operation can be performed, the screw tightening operation can be performed with high precision, and occurrence of screw tightening failure can be effectively prevented.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. A screw tightening robot according to the present embodiment, which is a screw tightening device, is configured by connecting a controller (not shown) to a screw tightening robot main body 1 as shown in FIGS. As shown in FIG. 2, the screw tightening robot main body 1 is roughly divided into a screw tightening head 2, a fixing flange 3 that supports the screw tightening head 2 and is attached to a mounting stay, It is provided with a connector box 4 for connecting the head unit 2 and a controller. In the following description, the direction shown in FIGS. 2 and 3 is described as a front for convenience.

The screw head 2 is constructed as shown in FIG. That is, a guide bar 6 extending in the vertical direction is supported by the fixedly arranged base block 5 through the linear guide 7 so as to be vertically movable and penetrate. An upper bracket 8 and a lower bracket 9 are attached to both upper and lower ends of the guide bar 6. A rack 10 which is located on the right side of the guide bar 6 in the figure and extends vertically is attached between the upper bracket 8 and the lower bracket 9, and the rack 10 is provided in the base block 5. Pinion 11 meshing with 10
Is provided.

On the right side of the base block 5 in the drawing, a vertical shaft motor 12 composed of, for example, a servomotor is mounted in a horizontal direction, and the rotation shaft of the vertical shaft motor 12 is connected via a coupling 13 to the pinion. 11 are connected. Thus, the guide bar 6 and the upper and lower brackets 8 and 9 are freely moved up and down with respect to the base block 5 by driving the vertical shaft motor 12, so that the advance / retreat movement mechanism is provided. It is configured.
A connecting bar 14 is provided between the upper bracket 8 and the lower bracket 9 on the left side of the guide bar 6 in the drawing.

In the left side of the lower bracket 9 in the drawing, a downwardly projecting mounting cylinder portion 15 is integrally provided. A bearing cylinder 16 is attached to the lower end of the mounting cylinder 15, and a plurality of bearings 18 are provided in the bearing cylinder 16 such that a drive shaft 17 penetrates vertically.
It is rotatably supported via. A bit (driver bit) 19 for screwing is detachably attached to the tip (lower end) of the drive shaft 17 by, for example, screwing.

In the lower half of the bearing cylinder 16,
Vacuum passage 2 for suction located around drive shaft 17
0 is formed. The distal end of the suction tube 21 is connected to the side surface of the bearing cylinder 16 so as to communicate with the vacuum passage 20. The base end side of the suction tube 21 is connected to the negative pressure generator 2 attached to the upper bracket 8.
2 are connected. Further, a negative pressure sensor 23 is provided at a tip side portion of the suction tube 21.

Further, at the lower end of the bearing cylinder 16,
The suction pipe 24 is attached by, for example, screwing. The tip end of the bit 19 is positioned to be slightly retracted into the suction pipe 24.
The drive shaft 1 is provided inside the suction pipe 24.
7 and the bit 20, the vacuum passage 20
Is formed so as to communicate with the suction air passage. When the negative pressure generator 22 is driven, the inside of the suction pipe 24 becomes negative pressure, and the head of the screw 45 (see FIG. 7) is sucked and held at the tip thereof. The bit 19 engages with the screw head.

On the other hand, a motor mounting tube 25 is mounted on the upper portion of the mounting tube portion 15.
A bit motor 26 composed of, for example, a servomotor is attached to the upper end of the head 5 downward. A rotating shaft 26 a of the bit motor 26 is connected to a torque sensor 28 via an upper coupling 27 in the motor mounting cylinder 25.
, And further connected to the drive shaft 17 via a lower coupling 29 in the mounting cylinder portion 15.

As a result, when the bit motor 26 is driven, the drive shaft 17 and thus the bit 19 rotate about the vertical axis (Z axis), thereby forming a rotation mechanism. It is. As shown in FIG. 2 and the like, the left side portion (the portion from the negative pressure generator 22 to the mounting cylinder portion 15) of the screwing head portion 2 is covered with a cover 30. The electric wiring (flat cable) 31 connected to the bit motor 26 and the like is flexible and is connected to the upper surface of the fixing flange 3. Further, the screw tightening head 2 has the same configuration as the head of the 4-axis screw tightening robot developed by the present applicant, and is designed to be shared.

As shown in FIGS. 2 and 4, the fixing flange 3 has a substantially rectangular box shape with a left side opened in the figure, and the left end surface thereof is formed with the screw tightening head 2.
Is fixed to the base block 5 by screws. At this time,
Vertical shaft motor 12 protruding rightward from base block 5
Are accommodated inside the fixing flange 3. In the right half portion of the fixing flange 3 in the drawing, the screwing robot body 1 is fixed to the mounting stays 32 and 33 (see FIG. 1) at three positions of front, back and lower surfaces. Is provided. In addition,
When it is necessary to distinguish the three mounting portions 34, (A), (B), and (C) will be appended to the reference numerals for convenience.

That is, as shown in FIG. 2 and FIG.
At the front part of the fixing flange 3, an attachment part 34 (A) is provided. The attachment portion 34 (A) is formed by forming two tap holes 36 on the upper and lower sides in two thick portions 35 on the left and right sides provided in the front portion of the fixing flange 3 so as to extend vertically in a strip shape. It is configured. These four tapped holes 36 in total
Are positioned corresponding to four screw insertion holes (not shown) formed in the mounting stays 32 and 33.

As shown in FIG. 4 (b), a mounting portion 34 (B) provided on the back surface of the fixing flange 3 also has a total of four tapped holes in two thick portions 35. 36 are formed. Further, as shown in FIG. 4C, a mounting portion 34 provided on the lower surface of the fixing flange 3 is provided.
(C) also has a configuration in which a total of four tapped holes 36 are formed in the two thick portions 35. In addition, a knock pin is provided at the center of each of the two thick portions 35. Hole 37
Are formed.

With such a configuration, as will be described in the following description of operation, the fixing flange 3 is attached to one of the mounting portions 3.
By selectively attaching to the mounting stays 32 and 33 at 4, the screw tightening head 2 can be installed in the vertical or horizontal direction.

The electric wiring 31 led out from the screwing head 2 is connected to the left end of the upper surface of the fixing flange 3, passes through the fixing flange 3, and is attached to the right end of the upper surface of the fixing flange 3. Connected to the connector box 4. As shown in FIGS. 2, 5, 6, etc., the connector box 4 has a rectangular box shape, and has a connector portion 4a on one side surface thereof. A connection cable 38 (see FIG. 2) for connecting to the controller is connected to the connector section 4a. The bottom of the connector box 4 is open,
Electrical wiring from inside the fixing flange 3 is passed through this portion.

At this time, in this embodiment, the mounting direction of the connector box 4 to the fixing flange 3 can be changed. That is, as shown in FIGS. 6B and 6C, two stays 39 are provided on the left side of the upper surface of the fixing flange 3 at the front and rear edges, respectively, in a rising shape. Each of these stays 39 has a female screw portion 39a.
Are formed. On the other hand, as shown in FIGS. 6 (a) and 6 (b), two screw insertion holes 40 are formed at the lower side on four front, rear, left and right surfaces of the connector box 4, respectively.

As will be described later, for example, at the time of shipment from the factory, the connector box 4 is attached to the fixing flange 3 on the stay 39 on both sides of the connector portion 4a by screws 41. Therefore, the direction in which the connector portion 4a is directed, in other words, the connection cable 3
The direction from which 8 is derived is the right side (the direction of the arrow (a) in FIG. 5). Then, from that state, the direction of the connector box 4 can be changed to the front direction (arrow (b) direction in FIG. 5) or the rear direction (arrow (c) direction in FIG. 5).

Although the detailed description of the configuration of the controller is omitted, the controller includes a microcomputer and the like. As will be described in a later description of the operation, during execution of the screw tightening operation, based on a control program stored in advance, a detection signal of each sensor, and the like, four of engagement, screwing, tightening, and torque holding are performed.
The two steps are sequentially performed at a predetermined bit rotation speed and a predetermined screw holding force, respectively.
(The vertical shaft motor 12, the bit motor 26, the negative pressure generator 22, etc.). At this time, the user can freely set the bit rotation speed and the screw holding force in each process.

Next, the operation of the above configuration will be described. First, the screw tightening robot main body 1 of the present embodiment can take several mounting forms to the mounting stays 32 and 33 by the plurality of mounting portions 34 provided on the fixing flange 3. That is, as shown in FIG. 1A, when the work 43 is to be screwed vertically on the work 43 on the base 42 of the work equipment, for example, the front surface of the fixing flange 3 is attached to the mounting stay 32. Mounting part 34
It is mounted so as to address (A).

In this case, when performing the mounting work,
The bolts 44 may be fastened to the four tap holes 36 of the mounting portion 34 through the four screw insertion holes formed in the mounting stay 32. Although not shown in the drawing, similarly, if the fixing flange 3 is attached at the attaching portion 34 (B) on the back side of the fixing flange 3, the fixing flange 3 is located at the front side of the attaching stay 32 in FIG. You can also. Thus, the screw tightening robot main body 1 can be installed in a vertically installed state in which the axial direction (screw tightening direction) of the screw tightening head unit 2 is the vertical direction.

On the other hand, as shown in FIG.
In the case where the screw fastening operation is performed in the lateral direction with respect to the fixing flange 3, the fixing flange 3
It is attached so as to face the attachment portion 34 (C) on the bottom surface of the. Also in this case, it can be attached by bolting in the same manner as described above. At the same time, a knock pin (not shown) is driven into the knock pin hole 37 (see FIG. 4C), thereby effectively preventing displacement or the like. can do.
Thus, the screw tightening robot main body 1 can be installed in a horizontal state in which the axial direction (screw tightening direction) of the screw tightening head 2 is set to the horizontal direction.

Accordingly, the screw tightening robot main body 1 of the present embodiment can cope with both cases where the axial direction is set to the vertical direction and the horizontal direction with one kind of fixing flange 3. At this time, unlike the conventional articulated screw tightening robot, since it is directly mounted on the mounting stays 32 and 33, no space (so-called dead space) is required for turning the arm or the like, and space is saved. It is also possible to easily support the own weight when the axial direction is set to the lateral direction.

Further, the screw tightening robot body 1 of the present embodiment
In, the mounting direction of the connector box 4 with respect to the fixing flange 3 can be changed as follows. That is, at the time of shipment from the factory, for example, as shown in FIGS. 2 and 5, the direction in which the connector portion 4 a of the connector box 4 faces, in other words, the direction in which the connection cable 38 is led out, is the right side surface (arrow in FIG. 5). (B) direction).

When it is desired to change the direction of the connector portion 4a of the connector box 4 to, for example, the front (the direction of the arrow (b) in FIG. 5), first, as shown in FIG. Remove the screw 41 attached to 39. Next, as shown in FIG. 6 (b), the connector box 4 is lifted slightly upward, and further, as shown in FIG. 6 (c), rotated by 90 degrees so that the connector portion 4a faces the front. Then, the connector box 4 is lowered again.
At this time, the female screw hole 39a of each stay 39 and the screw insertion hole 40 on the surface of the connector portion 4a of the connector box 4 and the surface on the opposite side thereof coincide with each other.
As shown in (d), the screw 41 is tightened and fixed. Further, the operation of changing the direction in which the connector portion 4a faces to the rear surface (the direction of the arrow (c) in FIG. 5) can be performed in the same manner.

Thus, the direction in which the connecting cable 38 is led out from the connector box 4 can be changed arbitrarily. For example, the space in which the mounting portion 34 of the fixing flange 3 is used and the environment in which the device is installed are limited. By arranging the connector box 4 in the most advantageous direction, it is possible to further save space. Incidentally, in FIG. 1A, the direction of the connector portion 4a (the direction in which the connection cable 38 is led out) is the right direction in the drawing (the direction (A) in FIG. 5), and in FIG. The direction (direction in which the connection cable 38 is led out) is the front direction in the figure (the (b) direction in FIG. 5).

The screw tightening robot main body 1 (screw tightening head 2) of this embodiment is controlled by a controller.
The screw tightening operation is executed under the control as shown in FIG. That is, the screw tightening operation is performed by sequentially executing four steps (process) of meshing (first period), screwing (second period), tightening (third period), and torque holding (fourth period). In each step, an appropriate bit rotation speed (rotation speed of the bit motor 26) and screw holding force (rotation torque of the vertical shaft motor 12) that are set in advance are obtained. Also, here, by detecting the screw head height and the screw tightening torque while performing the screw tightening operation, an inspection as to whether the screw tightening operation is normally performed is simultaneously performed.

First, in the step of engagement (first period), the bit rotation speed is set to the medium speed, and the screw holding force is weakened. As a result, the tip of the bit 19 and the groove (for example, a cross hole) in the head of the screw 45 are securely engaged with each other, and the inclination and locking of the screw 45 are prevented. In the next screwing (second period) step, the bit rotation speed is set to a high speed, and the screw holding force is set to a medium level. Thus, the screw 45 is screwed into the screw hole 43a of the work 43 in a short time.

In the step of tightening (third period), the screw holding force is increased while the bit rotation speed is kept low. Thus, the screw 45 is strongly tightened, and the groove of the screw head is prevented from being crushed. In the last step of holding the torque (fourth period), the rotation of the bit 19 is stopped, and the strong screw holding force is held. During this time, it is examined and confirmed that the screw soot and the screw tightening torque have increased, and the screw tightening operation is completed.

As described above, the precise control suitable for the screw tightening operation is performed, so that unlike the conventional single-axis screw tightening machine, high accuracy (for example, torque accuracy of ± 1%) is obtained.
3%), and the occurrence of defects during screw tightening, such as poor screwing, poor screwing, and oblique tightening, can be greatly reduced. As a result, application to an automatic assembly line or the like becomes sufficiently possible.

As described above, according to the screw tightening robot main body 1 of the present embodiment, it is possible to greatly reduce the size of the conventional screw tightening robot compared with the conventional four-axis articulated screw tightening robot, and to save space and relatively inexpensively. Is what you can do. In addition, by using one type of fixing flange 3, the screw tightening head 2 can be installed not only in the vertical direction but also in the horizontal direction as well as in the vertical direction and the horizontal direction. can do.

Further, in this embodiment, the connector box 4 is provided so that the mounting direction can be changed with respect to the fixing flange 3, so that the connector box 3 is arranged in the most advantageous space-wise direction. And further space saving can be achieved. In addition, the servomotors 12 and 26 are employed for the rotation mechanism and the forward / backward movement mechanism, and precise control is performed by the controller at the time of the screw tightening operation, so that the occurrence of screw tightening failure can be effectively prevented. Benefits can also be obtained.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention, and is a front view showing a vertical installation type (a) and a horizontal installation type (b) of a screw tightening head.

FIG. 2 is a front view showing a screw tightening robot main body.

FIG. 3 is a longitudinal sectional front view of a screw tightening head.

FIG. 4 is a diagram showing a front surface (a), a rear surface (b), and a bottom surface (c) of a fixing flange.

FIG. 5 is a top view of the screw tightening robot main body.

FIG. 6 is a diagram sequentially illustrating a procedure for changing the mounting direction of the connector box.

FIG. 7 is a diagram for explaining a process of screw tightening work.

[Explanation of symbols]

In the drawings, 1 is a screw tightening robot body (screw tightening device),
2 is a screw tightening head, 3 is a fixing flange, 4 is a connector box, 12 is a vertical shaft motor, 17 is a drive shaft, 19 is a bit, 24 is a suction pipe, 26 is a bit motor, and 32 and 33 are mounting stays. , 34 are mounting parts, 36
Is a tap hole, 38 is a connection cable, 39 is a stay, 4
0 indicates a screw insertion hole, and 45 indicates a screw.

Claims (3)

[Claims] 1. A screw head having a rotation mechanism for rotating a screw bit about an axis and an advancing / retreating mechanism for moving the screw bit in the axial direction, and supporting the screw head. And a fixing box attached to the mounting stay, and a connector box provided on the fixing flange for connecting the screw-fastening head portion to a controller. The fixing flange has a plurality of mounting portions. By being selectively attached to the attachment stay at any one of the attachment portions, the axial direction of the screwing head portion can be used as a vertical direction or a horizontal direction. And screw tightening device. 2. The screw fastening device according to claim 1, wherein an attachment direction of the connector box with respect to the fixing flange is changeable. 3. The controller according to claim 1, wherein, when a screw tightening operation is performed, the four steps of engagement, screwing, tightening, and torque holding are sequentially performed at a predetermined bit rotation speed and a predetermined screw pressing force, respectively. 3. The screw tightening device according to claim 1, wherein the screw tightening head is controlled.