JPS59146759A - Automatic screwing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic screwing device, particularly in a 5-bolt and nut device, when the relative axis inclination of the bolt and the nut is installed within a predetermined value. and depending on the relative axial displacement of the nut.

Along with automatically installing bolts and nuts.

This invention relates to an automatic screwing device suitable for expanding the tolerance of relative axial displacement and relative axial inclination between bolts and nuts. Tasu.

There are automatic machines that automatically tighten bolts, but if the relative axial inclination or relative axial displacement of the bolt and nut varies! However, it is difficult to engage the bolt and the first two or three bolts, and the technique has not yet been established.

The present invention thus solves the problem of Bo/L=
The work of installing the two parts is relatively easy. The relative axes of the bolt and nut can be fixed by automating the structure and control method of the device, and by flexibly holding the bolt or bolt and adding play to the holding. The purpose is to expand the allowable value of variation in core inclination and the allowable value of variation in relative axis displacement between bolts and nuts.

A problem in automatic bolt and nut systems is the misalignment of the positions and angles of the central axes of the bolt and nut. If the position or angle of the central axes of the bolt and nut is large, it will be impossible to mount the bolt and nut.

In other words, when the nut is pressed against the bolt and the nut is rotated in the screwing direction.

If there is a large deviation in the position or angle of the central axis, the nut may slip and rotate while in contact with the bolt, or the bolt and nut may not mesh properly, resulting in jamming and damage to the bolt or nut. Or, even if the bolt and nut are initially attached to each other, as the nut is further rotated and tightened, the part where the nut and bolt engage will gradually be removed from the center of the rotating shaft that turns the nut. Therefore, a large frictional force is generated between the nut and the bolt, which makes it impossible to fully attach the nut to the bolt.

However, if the position and angular deviation of the central axes of the bolt and nut are within a predetermined value, the bolt or nut can be properly installed as long as there is no damage to the bolt or nut.

In other words, in the present invention, if the angular deviation between the central axes of the bolt and nut is within a predetermined value, even if the central axes of the bolt and nut are misaligned, the above-mentioned positional deviation is set to the predetermined value. Position the nut or bolt so that it fits within the specified range, so that the bolt and nut can be completely installed, and even if there is some deviation in the angle or position of the mutual axes of the bolt and nut, it is easy to do so. By using a flexible mechanism that holds both of them in a flexible relationship so that they can be attached to each other, and by using a holding mechanism that creates an appropriate play between them, the axial center of the bolt and nut can be easily aligned. , and expand the allowable value of angular deviation. Furthermore, by using a detector that detects the installation status of bolts and nuts, it is possible to detect the possibility of misalignment or angular misalignment of the axes of the bolt and nut if they are installed outside the allowable range. In addition to detecting this, even if the positional misalignment and angular misalignment of the axes of the bolt and nut are within the allowable range, even if the bolt or nut is damaged and cannot be installed, this state can be detected and the state of the bolt and nut can be detected. The purpose of this invention is to provide a device that displays or issues information according to the situation.

That is, the present invention.

(b) Means for positioning the axes of the bolt and nut at predetermined positions, (Means for flexibly pressing the bolt and nut against each other.

←Means for rotating the bolt or nut in the direction of screwing the bolt and nut into each other;
... To provide an automatic screwing control system for bolts and nuts, including means for displaying or warning an abnormal state when the bolts and nuts are not properly installed.

More specifically, in the above committee*□□□ method, (a)
It is used as a means to flexibly press the bolt and the NAND against each other, and is deformable in the axial direction and in the direction perpendicular to the axial center.
and using a flexible mechanism that is deformable around the axis, and (b) means for calculating the amount of deformation of the flexible mechanism around the axis.

A means for detecting the amount of deformation in the axial direction of the above-mentioned flexible mechanism, and an automatic bolt/nut screwing control method provided with the following.

Furthermore, in the melon seeding method, the positioning means is configured to adjust the axial position of the bolt or nut to a predetermined position by the output of a detector that indicates the axial position of the bolt or nut. The present invention also provides an automatic screwing control system for bolts and nuts, characterized in that the system includes positioning means.

More specifically, (a) means for positioning the axes of the bolt and nut at predetermined positions, (b) means for flexibly pressing the bolts or nuts against each other, and the direction in which the bolts or nuts are screwed into each other. means for rotating the bolt or nut by a predetermined amount; means for detecting the reaction force around the axis from the bolt or nut and the amount of mutual axial displacement between the bolt and nut
.

■ If the reaction force is less than the predetermined amount and the amount of movement exceeds the predetermined value 1, then the bolt or ginnut is further rotated in the direction of screwing in, and the sword is rotated below the predetermined value 4. If the amount of movement is less than the specified value, the rotation of the bolt or threaded bolt will be stopped, and an abnormal condition will be displayed or reported, and the reaction force will be removed. In the case where the bolt or nut is rotated by a certain amount in the opposite direction to the screwing direction, the bolt or nut is rotated by a certain amount, and then an abnormal state is displayed or warned.

The above-mentioned control method is illustrated in a diagram as shown in FIG. 7. In other words, 1. This control method is divided into two stages. One is to roughly align the bolt and nut in the center, and 1":) is to insert the bolt and nut.

In this case, the approximate center alignment of the bolt and nut,
-19 Initial positioning is not necessary when both are relatively installed with predetermined accuracy. Further, if the two are not installed relative to each other with a predetermined accuracy, the position of one is detected and the other is installed at a predetermined position according to the detected position.

The method used in the examples of the present invention is shown below.

FIG. 8 shows a flowchart of the control method for aligning the bolt and nut at their approximate centers. Here, first, the approximate center position of the bolt is detected by the feeding mechanism 6, and the bolt is fed in two directions until it comes into contact with the bolt. When it comes into contact with the bolt,
Its contact position Z o in the Z direction.

Memorize the Z-direction position of the bolt, then move it back in two directions (a predetermined amount), and then feed it in the X-direction.

At the point of contact with the bolt, contact position XO1 in the X direction of the book
In other words, the X direction of Pol I (, i'4 V<) is memorized.The contact detector 4 in FIG.
, 43.47 are used. N, :l to the bolt position (
Xo, Zo) to complete the approximate positioning of the nut and bolt within the X and TZ planes.

Next, in order to perform alignment in the Y direction, the nut is fed in the Y direction until it contacts the bolt. The Y-direction position YO of the contact point is memorized as the screwing start point. For this control, a 3'mth detector 31, which will be described later, is used.
Ru. The above is the approximate center alignment of the bolt and dead. □Figure 149 is a flow chart for screwing a bolt and nut together.

First, during the process of screwing the Nand into the bolt, the detector 32 in Fig. 3, which will be described later, indicates that a biting occurred.
If this is detected, in order to release the lock, unwind the screw in the opposite direction to the screwing direction and then stop the rotation. Next, it shows on the display device that J's falling □ has occurred, and also sends a notification to the alarm device V that this has occurred. □, if no biting occurs □, it is determined whether or not it is smooth by the outputs of the detector 3□1 and the detector 3''2, and if slippage occurs, check whether the nut □ is slipping. It stops the rotation, indicates on the display that a slip has occurred, and issues an alarm on the alarm device. □If it is not slipping, there is a possibility that the nut is screwed into the boat bolt, so continue the screwing operation until the firewood picking position.

Below 1. Examples provide a detailed illustration of the invention. First, FIG. 1 shows the general configuration of the equipment to which the present invention is applied. Here, 1 is X'', y'
, z-direction == possible positioning mechanism, which is driven by a DC servo motor 1.1, 12.13.

The nut screwing mechanism 2 includes a pulse motor 36 for rotating the nut. A flexible mechanism coupled to the rotating shaft of the pulse motor 36 that can be deformed in the axial direction, a detector that detects the amount of deformation of the flexible mechanism, and a flexible mechanism that can be deformed in one rotation direction of the axial rotation and its A special mechanism 3 such as a detector for detecting the amount of deformation of the flexible mechanism and a flexible buttocks that can be deformed in the direction perpendicular to the axis that supports the holding mechanism 21 of the nut 10; It's more composed than 23M.

In addition, the holding mm21 of the nut □ is structured in a curved manner with a moderate play between the ridge and the nut 10.

Here, the tuna i mechanism 21 of Nareto'10 can be changed in a direction perpendicular to the axis, and the tuna mechanism 21 can be moved in the direction perpendicular to the axis. By supporting the nut 10 with a flexible mechanism 23 that is flexible and providing an appropriate play between the nut 10 and the holding mechanism 21 of the nut 10, the bolt and nut can be screwed together. Expand the allowable values for the axis position and axis angle. be able to.

By employing the structure as described above, the relative positioning accuracy of the bolt and nut can be lowered compared to the case where such a structure is not adopted.

The details are shown in FIGS. 3 and 4 and will be explained in detail later. Further, a bolt approximate center position detector is comprised of 41 to 47. The details are shown in FIG. 2 and will be explained in detail later.

The structure and operation of the bolt I-determined center position detector and the NAND screw-in mechanism in the embodiment of the present invention will be explained in detail. First of all, FIG. 2 shows an embodiment of the pole If-heat center position detection mechanism 40, in which X-direction and Z-direction detectors 41'
, 42 is fixed to the rotating shaft 43 and is rotatable around a rotating bearing 44. The lever 45 is fixed to the rotating shaft 43 and converts the rotation of the rotating shaft 43 into vertical displacement.

46 and 47 are contact detectors that detect the displacement of the detection lever and use microswitches. By using contact detectors 47, 46 in the X direction and two directions,
So; n, -f: A, X direction, Z direction detector 41.4
It becomes possible to detect minute displacements due to contact with the second bolt. In order to attach the nut to the bolt, it is necessary to align the chamfered portion of the nut and the chamfered portion of the bolt in four positions, that is, to roughly align the center of the two. In the initial state, the bolt and nut are approximately centered.

If this has not been done, the present approximate center position tit detector is used to perform such approximate center alignment. If the approximate center positions of the bolt and nut are aligned in the initial state, this strategic center alignment is not necessary. As the first step, as shown in Figure 6,
(> the tactile finger 4), the positioning machine h of FIG.
' Move the table 7 times in two directions. (b) As the detection finger 42 comes into contact with the bolt as shown in FIG. 6(2), the contact detector 46 operates. At that time, the Z-axis position of the positioning mechanism 1 in FIG. 1 is memorized.

Next, as shown in (3) in Figure 46, move the detector 4 back in the Z direction by a predetermined amount, and as shown in (4) in Figure 6, move the detector 4 in the X direction.
When 0 is moved, the detector 41 comes into contact with the bolt, so the contact detector 47 operates and similarly stores the X position of the bolt in the X-Z plane. By aligning the nut holding mechanism with the bolt position in the X-Z plane stored in this manner, the approximate center positions of the bolt and nut can be aligned.

3 and 4 are diagrams showing details of an embodiment of the nut screwing mechanism 2. FIG. 10 is a nut for screwing into the bolt, and 21 is a nut holding mechanism that holds the nut 10. This arm is coupled to a rotating torque transmission shaft 24 via a flexible mechanism 23 that is deformable in the axial direction and tilted and deformable around the axial center. Reference numeral 22 denotes an elastic support body for counteracting the weight of the nut holding mechanism 21. The rotational torque transmission shaft 24 is restrained in the direction of rotation about a 1 m center by a rotational displacement shaft 25, and is elastically supported in the direction of the center by a spring 27. The axial displacement detection lever 37 is fixed to the rotary torque transmission shaft 24 and transmits axial displacement to the axial displacement detector 3. The main rotation displacement shaft 25 is restrained in the axial direction by a housing 26 fixed to the rotation shaft 35 of a pulse motor 36, and is restrained by a spring 33 and a spring 33 in the rotation direction around the shaft center. According to 34,
It has elastic support. The rotational displacement detector 32 fixed to the housing 26 detects the rotational axis 35 and the rotational displacement axis 2.
It is possible to detect the relative angular displacement with respect to 5. In summary, a flexible mechanism 3 that can be deformed in the axial direction and an axial displacement detector 31 that detects the amount of deformation of the flexible mechanism portion detect the force of the nut being pressed against the bolt, and determine the rotational direction of the shaft 35. Flexible + that can be transformed into! 1. The rotational displacement detector 32 detects the amount of deformation of the structure 3 and its flexible mechanism, making it possible to detect the torque in the rotational direction applied to the bolt when screwing the nut into the bolt.

28i29.30 in FIG. 3 is a slip ring, which is used to transmit the outputs of the axial displacement detector 31 and the rotational displacement detector 32 to the outside.

This makes it easier to screw in nuts.

When the nut is controlled while being rotated continuously, it becomes l:iT function. ...The control method for the actual nut screwing operation will be explained below. @The approximate center position detector 40 allows Sivolt 50 and Nut 1 to be
Rough center positioning in the X-Z plane of 0 has already been completed.

Next, in order to align the cutting and screwing control mechanism in the Y direction, the positioning mechanism 1 shown in FIG. 1 moves the bolt in the direction of the tip. When the nut reaches a certain value or more, the axial displacement detector 31 operates and determines that the nut has contacted the bolt. father,
As a result, pressing the nut against the bolt in a predetermined manner also applies pressure. Then, the position of contact of the nut with the bolt in the Y direction is stored as YO, and the positioning of the cut to the tip of the bolt is completed.

FIG. 5 shows the bolt 50 and nut 10 screwed together, where nut 0 is the bolt.

In order to be able to engage with 50 and serve.

Assuming that the bolt is 1.0, the relative inclination angle θ of the axis of l-50 must be less than a certain value 00. If the inclination angle δ is smaller than a certain value θ0, a jamming or slipping phenomenon occurs, and it is impossible to engage the nut with the k-bolt.

Once the bolt and nut have been aligned, rotate the nut in the direction of threading in water. At this time, if the alignment of the axes of the nut and bolt and the alignment of the tab 9θ〈θO are guaranteed, the nut will be screwed in for the first time. If this is not the case, the following three phenomena of the 11th order occur.

■ When slipping occurs ■ When screwing in ■ Therefore, if θ and θ0 are guaranteed, there is no need to consider the slippage of the screws in ■ and ■. but,
In particular, the old control system is designed to be able to deal with the unlikely event that the bolt is installed in a condition that would cause the phenomenon (2) to occur.

The above applies when a normal nut and bolt are installed, but if the nut or bolt is damaged, the initial state will be set to the condition of θ<θO. Even so, the phenomena of ■ and ■ may occur.

In order to actually automate the screwing of bolts and nuts, it is necessary to detect binding and slippage caused by damage to bolts and nuts.

The detection method and processing method for each of the phenomena (1), (2), and (2) will be described below.

When biting (3) occurs, the biting increases the torque load and causes displacement in the rotational direction flexible mechanism. It is possible to use the rotational direction displacement detector 32 to detect that this displacement has exceeded a certain value. In other words, if the output of the rotational direction displacement detector 32 is obtained, it is determined that a biting has occurred, and the nut is given reverse rotation.After the biting is released, the rotation is stopped, and as will be described later. Detection of the occurrence of slippage in □②, which causes the control to proceed to the next control stage, is carried out as follows. If the bolt and nut are in good condition, and the nut is at a relative axis inclination angle θ that allows screwing, the initial pressing will be due to force by rotating the cut a certain amount. Next, the nut is screwed onto the bolt, and the nut is displaced in the axial direction, that is, in the positive direction of the Y-axis. As a result, the initial pressing force is released, and the axial displacement detector 31 in the Y direction
The output of is inverted.

From the above, if the output of the rotational direction displacement detector 31 does not reverse even if a certain rotation is applied while the nut is pressed against the IC bolt with a predetermined pressure, this indicates that a slipping phenomenon has occurred. Judging by this, I stopped the rotation of the nut,
Control is transferred to the next control stage, which will be described later.

Here, a certain rotation is when the rotation angle is given to the nut in a state where the nut and bolt are at a relative axis inclination angle θ that allows screwing.

This is defined as a value greater than or equal to the rotational speed at which the output of the axial displacement detector 31 can be reversed. This rotational speed N is given by the following equation. In other words, SY N≧□+1 (rotation) (P = pitch of screw, 1) SY = amount of hysteresis of detector 32) Detection when screwing in (①) This is possible because the output of the axial displacement detector 31 is reversed in the process of applying a certain rotation to the nut while being pressed with an appropriate force. When this is detected, control is transferred to the next control step, which will be described later.

Next, the control method after the detection of the phenomena q), ①, and ③ and the processing for them are completed will be described.

First, when the nut is screwed into the bolt normally, when it is detected that the output of the axial displacement detector 31 is reversed, the axial displacement detector 31 The positioning mechanism 1 is fed until the positioning mechanism 31 operates. Screw the nut onto the bolt ``1.''n C
Therefore, it is displaced in the Y direction in accordance with the rotation of the twisting mechanism, and the output of the axial displacement detector 31 is reversed again.

When the above control is repeated, the feed position in the Y direction is added to the value of the contact point ftyo between the nut and bolt in the storage device, and from the screwing amount DY (this value is also stored in the storage device in advance as n). When the value becomes large, it is determined that the nut has been sufficiently screwed into the bolt, and the rotation of the nut is stopped and the screwing operation is completed.

Next, if it is detected that the phenomena of slipping and jamming have occurred, it is determined that the oblique angle θ around relative axis 1 is not within the range of θ≦θ0, or that there is damage to the bolt or nut. The display device displays the occurrence of , biting, or escaping, and the alarm device issues an alarm.

The mechanism and control described above automatically screws in bolts and nuts with a predetermined axial center position or axial center angle deviation, and also prevents bolts or nuts from being installed outside the above range. Alternatively, it is possible to determine that screwing is impossible due to damage to the bolt or nut, and to rule this out.

Father, although the example of screwing a nut onto a bolt is described here, this control method of the present invention can also be applied even when the bolt and nut are reversed, that is, when screwing a bolt into a nut. That should be obvious.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the structure of an embodiment of a bolt/nut screwing device to which the present invention is applied. FIG. 2 is a diagram showing the configuration of an embodiment of a detector for detecting the approximate center position of a bolt in a bolt/nut screwing device to which the present invention is applied. Figures 4 and 3 are sectional views showing embodiments of a nut screwing mechanism which is a main part of a bolt/nut screwing device to which the present invention is applied. FIG. 4 is a diagram showing an axial sectional view of FIG. 3. FIG. 5 is a diagram illustrating the relative postures of the bolt and nut so that they can be screwed together. FIG. 6 is a diagram illustrating the detection operation procedure of the detector for detecting the approximate center position of the bolt. FIG. 7 is a diagram showing a schematic procedure of an automatic bolt/nut screwing control system according to the present invention. FIG. 8 is a diagram showing the steps of roughly aligning the centers of the bolt and nut and applying a predetermined pressing force between the bolt and nut in the automatic bolt-nut screwing control method of the invention. Figure 49 is a diagram showing the procedure for screwing in a bolt and nut in the bolt-nut automatic screwing control system of the present invention. ,,5″ Skull 6 Figure j [ (3)
(4) No. 77, ! 3 different

Claims (1)

[Scope of Claims] (a) Means for positioning the axes of the screwed member and the screwed target member at predetermined positions. (b) Means for flexibly pressing the screw-in member and the target member to be screwed into each other; and (ii) Means for applying torque to the screw-in member in the direction of screwing the screw-in member and the member to be screwed into each other. (2) The threaded member and the core screw: means and means for detecting slippage and jamming between the parts to be threaded and the material. Automatic screwing device including.