JPH0560735U - Screw tightening device - Google Patents

Abstract

(57) [Summary] [Purpose] To reliably check the attraction of screws to a screw tightener without making a mistake, and to improve the efficiency of screw tightening work. [Structure] An insertion chamber 6 for adsorbing a head portion of a screw S and side holes 9, 9, ... For communicating the insertion chamber 6 with the outside are formed in a tip portion 1a of a screw fastening machine 1. A suction means 3 for sucking the screw S is connected to the screw tightener 1. The insertion chamber 6 is formed so as to block the communication between the insertion chamber 6 and the suction means 3 when the screw S is adsorbed along the screw tightening direction A. A pressure sensor for detecting the pressure of the air sucked from the screw fastener 1 when the tip 1a of the screw fastener 1 covers the periphery of the screw of the pallet P in a close contact state between the insertion chamber 6 and the suction means 3. 4 is provided. When the pressure sensor 4 detects a pressure value below a predetermined value, the suction of the screw S is confirmed, and when the pressure value above the predetermined value is detected, it is determined that the screw S is not sucked and an error signal is output. 5 is provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a screw tightening device that is used for assembling a work and automatically tightens a screw to a work after the screw is sucked and held, and more particularly to a mechanism for confirming the screw suction.

[0002]

[Prior Art]

 Generally, when assembling a workpiece in FA (Factory Automation), a screw tightening device that automatically tightens a screw is often used. Conventionally, this type of screw tightening device has been equipped with a screw tightening machine that tightens the screw adsorbed at the tip to the work surface, and the tip of which can be inserted into the groove of the screw head in the support cylinder of this screw tightening machine. Is supported so that it can be rotated and moved up and down, and an insertion chamber where a screw is sucked and adsorbed is formed inside the tip of the support cylinder, and an air chamber for adsorbing the screw is formed in this insertion chamber. It is well known that a suction means for sucking is communicated. Inside the insertion chamber, the dust generated during screw tightening is sucked by the suction means, and the lower end surface of the insertion chamber holds down the tightened components after screw tightening. The operation of pulling out the bit is made smooth and the working time is shortened.

When a screw is to be sucked by the screw tightener, suction is performed by the suction means above the screw on a pallet supplying the screw to suck and suck the screw into the insertion chamber. It is necessary to confirm that the screw is surely sucked at the time of sucking the screw. In the screw tightening device, the negative pressure of the sucked air is detected by the pressure sensor. In that case, the lower end surface of the insertion chamber approaches the pallet before the screw is sucked to reduce the gap with the pallet surface, so the vacuum sensor detects a certain negative pressure and the suction of the screw is erroneously recognized. Sometimes. For this reason, after removing the screws from the pallet, confirm that the screws have been pulled up from the pallet until the screw clamp is raised to a height where the gap between the lower end surface of the insertion chamber and the pallet surface becomes large to some extent. is doing. Then, after confirming the adsorption of the screw, the screw tightener is moved to the screw tightening position to tighten the screw.

[0004]

[Problems to be solved by the device]

 However, since the conventional screw tightening device raises the screw tightening machine once to check the screw sucking state while moving from the screw suction position to the screw tightening position, There is a problem that it slows down the tightening work and hinders the improvement of work efficiency.

The present invention has been made in view of such a point, and the purpose thereof is to surely confirm the suction of a screw without erroneously recognizing it and to improve the efficiency of the screw tightening work. It is intended to provide a screw tightening device.

[0006]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, a device according to claim 1 is a screw tightener for tightening a screw sucked at a tip end onto a work surface, and a moving means for moving the screw tightener from a screw suction position to a work surface. When air is sucked in communication with the above screw tightener and the suction means for sucking the screw into this screw tightener and the tip of the screw tightener cover the periphery of the screw of the pallet supplying the screw in a close contact state. , A pressure sensor that detects the pressure of the suctioned air sucked from the screw tightener, and when this pressure sensor detects a pressure value that is less than or equal to a predetermined value, check the screw adsorption and detect a pressure value that is greater than or equal to the predetermined value. And a control means for outputting an error signal when it is determined that the screw has not been sucked, and an insertion chamber for sucking the screw and sucking the screw head is formed at the tip of the screw tightener. This insertion room In a screw tightening device formed so as to block the communication between the insertion chamber and the suction means when a screw is adsorbed along the screw tightening direction, the tip of the screw tightening machine communicates the insertion chamber with the outside. It is configured to form a communication part that

A second aspect of the invention is dependent on the first aspect of the invention, wherein a plurality of the communication parts are provided at the same height position of the tip of the screw fastening machine at equal intervals in the circumferential direction. It is a structure to be formed.

[0008]

[Action]

 With the above construction, in the device according to claim 1, the moving means lowers the screw tightener so that the tip of the screw tightener tightly covers the periphery of the screw on the pallet surface. Is adsorbed and the pressure sensor detects the pressure of the sucked air. At this time, if the screw is adsorbed along the screw tightening direction, the insertion chamber and the suction means are cut off, so that the pressure sensor detects a pressure value (negative pressure value) below a predetermined value. Based on this detection signal, the control means surely confirms the screw suction and controls the screw tightening machine to move to the screw tightening position. On the other hand, when the screw is tilted and attracted, or when it is not attracted, the insertion chamber communicates with the suction means, and the air entering from the communication section raises the pressure of the suction air, so the pressure sensor is above the specified value. Based on this detection signal, the control means determines that the screw is not adsorbed in the specified posture, and outputs an error signal to prevent the screw tightener from moving to the screw tightening position. To control.

According to the second aspect of the invention, when the screw is sucked into the insertion chamber, air is evenly introduced from the communication portion at the tip of the screw tightening machine, so that the screw is sucked along the screw tightening direction. To be done.

[0010]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 and FIG. 2 show a screw tightening device according to an embodiment of the present invention, and 1 is a screw tightening device for tightening a screw S on a work surface. The screw tightening machine 1 is connected with a moving means 2 for moving the screw tightening machine 1 from a screw suction position to a work surface and a suction means 3 for sucking air into the screw tightening machine 1. The suction means 3 communicates with the screw tightener 1 so as to suck the screw S 1 onto the tip 1a of the screw tightener 1 by air suction.

The screw S is housed in a plurality of holes a formed in the pallet P so as to expose the screw head portion, and is arranged at a position different from the work. When the screw S is sucked by the screw tightener 1, the moving means 2 lowers the tip portion 1 a of the screw tightener 1 to the screw suction position on the pallet P mounted on the mounting table B and touches it. The tip end portion 1a covers the periphery of the screw S of the pallet P in a close contact state. In this state, the screw S is sucked by the suction means 3.

A pressure sensor 4 for detecting the pressure of suction air when the screw S is sucked is connected between the screw tightener 1 and the suction means 3. A control means 5 for controlling the movement of the screw tightener 1 is connected to the pressure sensor 4, and the control means 5 is adapted to screw the screw S when the pressure sensor 4 detects a pressure value below a predetermined value. After confirming the suction, the screw tightening machine 1 is controlled so as to continue moving to the screw tightening position, and when the pressure value above a predetermined value is detected, it is judged that the screw S is not sucked and the error signal is detected. Is output and the moving means 2 is controlled so as not to move the screw tightening machine 1 to the screw tightening position.

As shown in FIG. 2, an insertion chamber 6 into which the screw S is sucked and the screw head portion is adsorbed is formed at the tip end portion 1 a of the screw tightening machine 1. A screw suction hole 7 having a diameter smaller than the diameter of the head of the screw S is formed on the upper surface. The screw suction hole 7 communicates with the suction means 3, and the head of the screw S 1 is sucked by the suction of the suction means 3. In order to maintain the posture when the screw is sucked, a sucking surface 8 corresponding to the shape of the head of the screw S is formed at the lower end of the screw sucking hole 7 described above. The suction surface 8 is formed so that when the screw S is sucked along the screw tightening direction A, the communication between the insertion chamber 6 and the suction means 3 is blocked.

The predetermined pressure value when the pressure sensor 4 confirms the adsorption of the screw S on the screw tightener 1 is a pressure value measured when the screw S is adsorbed on the adsorption surface 8 in advance. Is.

A plurality of side holes 9, which are communication portions that communicate the insertion chamber 6 and the outside, are formed in the tip portion 1 a of the screw tightener 1 at the same height position at equal intervals in the circumferential direction. ing. With this configuration, the air sucked by the suction means 3 uniformly enters through the plurality of side holes 9, 9, ... And stabilizes the suctioned air distribution in the insertion chamber 6. , The screw S is adapted to be adsorbed to the adsorbing surface 8 along the screw tightening direction A. Moreover, even if the tip end portion 1a covers the periphery of the screw of the pallet P in a close contact state, the side holes 9 are provided so that if the screw suction hole 7 and the insertion chamber 6 communicate with each other, the air in the outer portion can be prevented. Is sucked into the suction means 3 through the screw suction hole 7.

As shown in FIG. 1, the screw tightening machine 1 includes a box-shaped main body 10 and a support cylinder 11 connected to the main body 10. A bit 12 for tightening a screw is inserted into and supported by the support cylinder 11 so as to be rotatable and vertically movable. The bit 12 is formed in such a shape that its tip 12a is fitted in the groove of the screw head, and is lowered and rotated with respect to the screw tightening position to perform screw tightening.

A drive motor 13 for rotating the bit 12 is attached to the upper portion of the main body 10. The drive motor 13 includes a drive transmission mechanism 14 housed in the main body 10 and the support cylinder. It is connected to the bit 12 via a transmission shaft 15 that passes through the inside of 11. The drive transmission mechanism 14 has a spline coupling portion 16 spline-coupled in the middle thereof, and the bit 12 can be rotated and moved up and down by the spline coupling portion 16.

Elevating means 18 for elevating and lowering the bit 12 is provided in the main body 10. The elevating means 18 is provided in the spline coupling portion 16 and is provided with the bit 12 via the transmission shaft 15. And an elevating cylinder 20 for raising the bit 12 against the urging force of the upper spring 19.

The drive transmission mechanism 14 includes the spline coupling portion 16, a rotary shaft 21 coupled to the spline coupling portion 16, a first gear 22 supported by the rotary shaft 21, and a first gear 22. And a second gear 23 that meshes with the second gear 23. The second gear 23 is supported by the tip of the drive shaft 24 of the drive motor 13.

The spline coupling portion 16 includes a spline groove (not shown) formed in the axis of the rotary shaft 21 and a spline shaft 26 slidably connected to the spline groove in the vertical direction. Become. The upper spring 19 for urging the spline shaft 26 downward is wound around the spline shaft 26.

The lifting cylinder 20 has a rod 30 whose tip is connected to an intermediate portion of a horizontally arranged lifting body 31, and the lifting body 31 is driven by the extension of the rod 30. It is designed to go up and down. The elevating body 31 is formed with an insertion hole (not shown) through which the transmission shaft 15 can be inserted at one end 32 with the tip end of the rod 30 sandwiched therebetween. With this insertion hole, the drive transmission mechanism 14 is inserted. The transmission shaft 15 is allowed to rotate, and the bit 12 is raised by pushing up the spline shaft 26 when the lifting body 31 is raised. Further, when the ascending / descending body 31 descends, the upper spring 19 is released from the pressing force of the elevating / lowering body 31 so as to urge the spline shaft 26 downward. Is descending.

The support cylinder 11 is composed of a fixed cylinder 35 fixed to the main body 10 and a telescopic cylinder 36 provided at the lower end side of the fixed cylinder 35 so as to be movable back and forth with respect to the fixed cylinder 35. The telescopic tube 36 receives the external force (pressing force) from the work surface during the screw tightening work, and retracts into the fixed tube 35. Further, the lower end of the expandable cylinder 36 guides the tip of the bit 12. On the other hand, guide bars 37, 37 inserted into the fixed cylinder 35 are connected to the upper end of the expandable cylinder 36, and these guide bars 37, 37 are connected to a stopper plate 38 in the main body 10. Has been done. The stopper plate 38 prevents the telescopic tube 36 from falling off the fixed tube 35. Further, in the fixed cylinder 35, lower springs 39, 39 for urging the expandable cylinder 36 downward are provided. These both lower bars 39, 39 yield to the pressing from the work surface during the screw tightening work to cause the telescopic cylinder 36 to retract with respect to the fixed cylinder 35.

Above the stopper plate 38 in the main body 10, there is provided a pressing cylinder 40 that presses the telescopic cylinder 36 against the work surface when the bit 12 is raised after screwing. After the screw tightening work, the pressing cylinder 40 extends the rod 41 and presses the stopper plate 38 downward to bring it into contact with the lower surface of the main body 10, whereby the telescopic cylinder 36 is fixed to the upper position. The cylinder 35 is positioned at the most protruding position.

The suction means 3, the drive motor 13, the elevating cylinder 20 and the pressing cylinder 40 are connected to the control means 5, and the control means according to each step between the screw suction position and the screw tightening position. It is designed to operate by receiving a control signal from 5.

Next, the operation of this embodiment will be described. The moving device 2 lowers the screw tightener 1 so that the tip portion 1a of the screw tightener 1 tightly covers the periphery of the screw on the pallet surface, and in this state, the screw S is adsorbed by the screw tightener 1. The pressure sensor 4 detects the pressure of the suction air. At this time, when the screw S is adsorbed along the screw tightening direction A, the communication between the insertion chamber 6 and the suction means 3 is cut off, so that the pressure sensor 4 detects a pressure value equal to or lower than a predetermined value. Based on this detection signal, the control means 5 can surely confirm the attachment of the screw S. Then, the screw tightening machine 1 is controlled by the control means 5 so as to continuously move to the screw tightening position. As described above, when the screw suction is confirmed, the screw tightening machine 1 is not moved up and is performed in parallel with the normal screw suction process, so that the efficiency of the screw tightening operation can be improved. On the other hand, when the screw S is tilted and attracted or is not attracted, the insertion chamber 6 and the suction means 3 are in communication with each other, and air is introduced from the side holes 9, 9 ,. Since the pressure of the suction air is increased by the suction, the pressure sensor 4 does not mistakenly recognize the suction of the screw. At this time, the pressure sensor 4 detects a pressure value equal to or higher than a predetermined value, and based on this detection signal, the control means 5 judges that the screw S is not adsorbed in a predetermined posture and outputs an error signal. The screw tightener 1 is controlled so as not to move to the screw tightening position.

In the above-described embodiment, the communication portion of the tip portion 1a of the screw tightener 1 is formed by the side hole 9, but the shape of the communication portion is not particularly limited, and may be, for example, a notch shape such as a slit shape. It may be formed in a shape.

In the above embodiment, the control means 5 is configured to control the screw tightening machine 1 so as not to move to the screw tightening position when the pressure sensor 4 detects a pressure value equal to or higher than a predetermined value. For example, the control means 5 may be configured to output the warning signal after stopping the screw tightening machine 1.

[0029]

[Effect of the device]

 As described above, according to the screw tightening device of the first aspect, the communication between the insertion chamber and the suction means is not interrupted even if the tip of the screw tightener covers the screw periphery of the pallet surface in a close contact state. When the screw is adsorbed along the screw tightening direction, the communication between the two is cut off, so it is possible to reliably confirm the adsorption of the screw by the negative pressure when the communication is cut off. Also, when the screw is tilted and attracted, or when it is not attracted, suction air enters from the communication part that communicates with the outside and raises the air pressure, preventing the pressure sensor from erroneously recognizing screw adsorption. be able to. Furthermore, after the screw suction process, the screw tightening machine can be checked in parallel with the normal screw suction process without raising the screw tightening machine to check for screw suction. Can be improved.

According to the screw tightening device of the second aspect, the suction air uniformly enters from the plurality of communicating portions and stabilizes the suction air distribution in the insertion chamber. It can be adsorbed along the direction.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a screw tightening device according to an embodiment of the present invention.

FIG. 2 is an enlarged view of the relevant part.

[Explanation of symbols]

 1 Screw Tightening Machine 1a Tip of Screw Tightening Machine 2 Moving means 3 Suction means 4 Pressure sensor 5 Control means 6 Insertion chamber 9 Side hole (communication part) A Screw tightening direction S Screw

Claims (2)

[Scope of utility model registration request] 1. A screw tightening machine for tightening a screw adsorbed at a tip portion onto a work surface, a moving means for moving the screw tightening machine from a screw suction position to a work surface, and air suction by communicating with the screw tightening machine. When the suction means for adsorbing the screw to this screw tightener and the tip of the screw tightener cover the periphery of the screw of the pallet supplying the screw in a close contact state,
A pressure sensor that detects the pressure of the suction air sucked from the screw tightener, and when this pressure sensor detects a pressure value that is less than or equal to a predetermined value, confirms the screw adsorption and when a pressure value that is greater than or equal to a predetermined value is detected. And a control means for outputting an error signal when it is determined that the screw is not sucked, and an insertion chamber is formed at the tip of the screw tightening machine where the screw is sucked and the screw head is sucked. In the screw tightening device, the chamber is formed so that communication with the suction means is blocked when the screw is adsorbed along the screw tightening direction. A screw tightening device, characterized in that a communication portion that communicates with the outside is formed. 2. The screw tightening device according to claim 1, wherein a plurality of the communicating portions are formed at the same height position of the tip of the screw tightening machine at equal intervals in the circumferential direction.