JP2013180381A - Automatic screw fastening machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic screw fastening machine capable of simultaneously fastening nuts to both electrodes even for a workpiece such as a storage battery having electrodes of different polarities.SOLUTION: In an automatic screw fastening machine 1 comprising: a screw fastening tool unit 10 provided with each of a bit 6 engaged with a nut and a bit driving motor 5; and a reciprocating movement means 20 provided with each of a guide plate 12 allowing insertion of the bit 6 and a lifting/lowering driving motor 15 allowing reciprocating movement of the screw fastening tool unit 10, the automatic screw fastening machine is characterized in that each of a shaft coupling 2 and the guide plate 12 is constituted as an insulating material. Because electricity charged in the bit 6 is not transmitted to the inside of each of the bit driving motor 5 and the lifting/lowering driving motor 15, each of the bit driving motor 5 and the lifting/lowering driving motor 15 is not damaged.

Description

  The present invention relates to an automatic screw tightening machine that does not fail due to energization even when a bit engaged with a screw or nut is energized.

  As shown in FIGS. 5 to 7, the conventional automatic screw tightening machine 100 includes a screw tightening tool unit 70 including a bit 76 that can be engaged with a nut (not shown) as an example of a desired part and has conductivity. And a reciprocating means 80 capable of moving up and down the screw tightening tool unit 70 in the vertical direction.

  As the screw tightening tool unit 70, one shown in Patent Document 1 is known and will be described below with reference to FIG. The screw tightening tool unit 70 includes an AC servo motor (hereinafter referred to as a bit drive motor 5) that is an example of a rotational drive source having a rotatable output shaft 5a, and an insulating member that fixes the main body of the bit drive motor 5. 77, a casing 71 having a bearing 75 for fixing the insulating member 77 and passing through the output shaft 5a, a drive shaft 73 connected to the upper portion of the bit 76 and having conductivity, the bit 76 and The slip ring 74 made of a conductive material fixed between the drive shafts 73, the shaft coupling 78 that can insulate and connect the drive shaft 73 and the output shaft 5a, and the housing 71 are fixed. The bit 76 and the casing 71 are supported and configured to be electrically conductive so as to be electrically conductive. The conductive mechanism 72 is grounded by being grounded to the ground level GND. By the way, the screw tightening tool unit 70 may generate weak static electricity from the inside of the bearing 75 when the output shaft 5a rotates by the operation of the bit drive motor 5. The static electricity is charged in the outer ring of the bearing 75, the casing 71, the conductive mechanism 72, the slip ring 74, and the bit 76, respectively. Can flow to GND. That is, the conventional screw tightening tool unit 70 is characterized in that, even when a precision part such as an electronic part is fastened, static electricity does not accumulate in the bit 76, so that the precision part is not damaged by the static electricity.

  On the other hand, as shown in FIG. 5, the reciprocating means 80 is connected to an AC servo motor (hereinafter referred to as a lift drive motor 15) which is an example of a rotational drive source and an output shaft 15a of the lift drive motor 15. A ball screw 17 that rotates integrally with the output shaft 15 a, a movable member 18 that can reciprocate along the axis of the ball screw 17 by receiving the rotation of the ball screw 17, and a reciprocating motion integrally with the movable member 18. A mounting plate 19 for fixing the screw tightening tool unit 70, a frame 16 for fixing the lifting drive motor 15 and rotatably supporting the ball screw 17, and a guide for fixing the bit 76 to the outer periphery of the bit 76. And a plate 112. In addition, the bit 76 is inserted through the guide plate 112 and is arranged for restricting the shake due to the rotation of the bit 76. For this reason, since the guide plate 112 comes into contact with the bit 76, the respective contact portions are easily worn, and the guide plate 112 that is not a consumable part is a conductive material having higher wear resistance than the bit 76 that is a consumable part. Made of metallic material.

  Further, as shown in FIG. 7, the automatic screw tightening machine 100 is configured by arranging two automatic screw tightening machines 100, 100 when the work 50 has two fastening points (51, 52). At the same time, in order to shorten the fastening time, the two places are often lowered at the same time, and the fastening places are often fastened simultaneously. The automatic screwing machines 100 and 100 are respectively fixed to columns 92 and 92 arranged so as to extend vertically from the base 91, and the bits 76 and 76 are positioned above a predetermined fastening point (51 and 52). It is set to be. Further, the base 91 serving as a work table is wired and grounded to the ground level GND, and the screw tightening tool units 70 and 70 and the work 50 are connected to a common ground level GND.

JP 2000-153466 JP

  However, in the conventional automatic screw tightening machine 100, as shown in FIG. 7, when the work 50 is provided with electrodes 51 and 52 having positive and negative polarities, such as a storage battery, and stores electricity, it is simultaneously applied to the electrodes 51 and 52. The nut could not be fastened. This is because electricity stored in the work 50 is transferred from the bit 76 of the automatic screwing machine 100 on one side when the nuts fitted to the bits 76 and 76 are simultaneously brought into contact with both electrodes 51 and 52, respectively. This is because the guide plate 112, the frame 16, the column 92, the base 91 and the other automatic screwing machine 100 are turned. That is, the conventional automatic screw tightening machine 100 can transmit almost all of the static electricity to the ground level GND if the electricity is weak, such as static electricity, but has a relatively large potential difference like the electricity stored in the storage battery. If it is electricity, all this electricity cannot be transmitted to the ground level GND. For this reason, in the conventional automatic screw tightening machine 100, for example, electricity flows from the electrode 51 to the bit 6 on one side, the electricity flows to the electrode 52 via the other bit 6, and the work 50 is damaged. There was a problem. Further, in the process of short-circuiting both the electrodes 51 and 52 described above, the electricity stored in the work 50 is transmitted from the bits 76 and 76 through the output shafts 5a, 5a, 15a and 15a to the bit driving motor 5. , 5 and the elevating drive motors 15, 15 respectively. As a result, the bit drive motors 5 and 5 and the lift drive motors 15 and 15 are also damaged. In order to eliminate such breakage of each drive motor and breakage of the work 50, it is conceivable that the nuts are not fastened simultaneously to the electrodes 51 and 52 of the work 50. However, in this case, the operation control of the conventional automatic screw tightening machines 100 and 100 must be changed so that the reciprocating means 80 and 80 are moved up and down in opposite directions, and two nuts are installed. There is also a problem that the time for fastening is approximately twice as long as that for simultaneous fastening.

  The present invention has been made in view of the above problems, and an object thereof is to provide an automatic screw tightening machine capable of simultaneously fastening nuts to both electrodes even for a work having electrodes of different polarities such as a storage battery. In order to achieve this object, the present invention provides a screw tightening tool unit having a shaft coupling capable of transmitting rotation by integrally connecting an output shaft of a rotary drive source and a bit engaging with a desired part, and the bit. And a reciprocating means for enabling reciprocating movement of the screw tightening tool unit by driving a reciprocating drive source, wherein the shaft coupling and the guide plate are insulated from each other. The electric power charged to the bit is configured not to energize the rotary drive source and the reciprocating drive source, respectively. A pair of chuck claws provided with a holding portion capable of holding the components to be supplied as appropriate, and a chuck body that supports the chuck claws in a swingable manner and allows the insertion of the bit and the passage of the components respectively. A chuck unit including a pipe connected to the chuck body and having a passage hole through which the component can pass may be fixed to the guide plate. Further, it is preferable that a plurality of the screw tightening tool units and the guide plates are provided so that simultaneous fastening to a plurality of locations is possible.

  In the automatic screw tightening machine 1 of the present invention, since static electricity generated by driving each of the rotational drive source or the reciprocating drive source is not transmitted to the bit 6 by the shaft coupling 2 and the guide plate 12, the workpiece is damaged by static electricity. There is an advantage that can be prevented. On the contrary, if the bit 6 is energized by receiving electricity from the work 50, the electricity energized to the bit 6 is insulated by the shaft coupling 2 and the guide plate 12. They are not transmitted to the output shaft 5a of the rotational drive source and the reciprocating means 20, respectively. Therefore, the automatic screw tightening machine 1 has an advantage that the charged electricity of the bit 6 does not energize the rotary drive source and the reciprocating drive source, so that the rotary drive source and the reciprocating drive source are not damaged. is there. The chuck unit 30 may be attached to the guide plate 12. In this case, the automatic screw tightening machine 1 can supply the nut to the inside of the chuck unit 30 as appropriate and continuously tighten it. There is also an advantage that fastening work with high work efficiency can be performed. Furthermore, the conventional automatic screwing machines 100 and 100 of FIG. 7 are changed to the automatic screwing machines 1 and 1 of the present invention, respectively, so that the output shaft 5a of the rotary drive source is changed from the bits 6 and 6 as described above. 5a and the reciprocating means 20, 20 can be insulated. For this reason, even if nuts are simultaneously fastened to the electrodes 51 and 52 of the work 50 such as a storage battery that could not be fastened, the work 50 is not short-circuited. Therefore, the automatic screw tightening machines 1 and 1 according to the present invention can simultaneously fasten the nut to the workpiece 50, so that the fastening time can be minimized. Further, since the electricity of the workpiece 50 does not energize components other than the bit 6, the entire automatic screwing machines 1 and 1 are not energized, and the column 92 or the base 91 is not charged. Therefore, there is an advantage that an operator (not shown) does not get an electric shock even when touching the base 91 or the like and can perform the fastening operation safely.

It is a schematic explanatory drawing of one Example concerning this invention. It is a schematic explanatory drawing which shows another Example of this invention. It is a schematic explanatory drawing of the shaft coupling concerning this invention. It is a partially cutaway sectional view of a shaft coupling concerning the present invention. It is a schematic explanatory drawing of the conventional automatic screwing machine. It is a partially cutaway sectional view of a conventional screw tightening tool unit. It is a schematic explanatory drawing which shows the use condition of the conventional automatic screwing machine.

  An embodiment of the present invention will be described below with reference to FIGS. In addition, about the code | symbol demonstrated below, when it is the same as the code | symbol used in the above-mentioned FIG. 5 thru | or FIG. 7, it is a product equivalent to the conventional component.

  An automatic screw tightening machine 1 according to the present invention includes a screw tightening tool unit 10 that rotatably supports a bit 6 that engages with a nut or the like, and a mounting plate that is fixed to the screw tightening tool unit 10 and can be reciprocated vertically. And a reciprocating means 20 having 19.

  The screw tightening tool unit 10 insulates and connects the bit drive motor 5 capable of outputting a predetermined rotation speed and torque, the output shaft 5a that rotates by receiving the drive of the bit drive motor 5, and the bit 6. The shaft coupling 2 is constituted.

  The bit drive motor 5 is connected to a driver control device (not shown), and is configured to be able to rotate the output shaft 5a at a predetermined rotational speed in response to a command from the driver control device. Further, the bit drive motor 5 is connected to the ground level GND, and is configured to be able to ground static electricity charged on the bit drive motor 5.

  As shown in FIGS. 3 and 4, the shaft coupling 2 includes an output shaft connecting portion 2a that connects the output shaft 5a, a bit connecting portion 2b that connects the bit 6, the output shaft connecting portion 2a, and the It is comprised from the insulation connection part 2c interposed between the bit connection parts 2b.

  The output shaft connecting portion 2a communicates with a fitting portion 120 having a substantially square cross section that fits on the tip portion of the output shaft 5a and a fitting hole 124 through which an insulating shaft 150 described later can be inserted. It is provided as follows. Further, the output shaft connecting portion 2a is provided with a protruding portion 123 protruding at the end thereof, and on the other hand, two tap holes 122 (similar to the tap holes 132 and 132 in FIG. 4) so as to extend from the outer periphery toward the axis. ) Are provided opposite to each other. A pilot hole of the tap hole 122 passes through the inner wall surface of the fitting portion 120 across the output shaft connecting portion 2a. Further, the output shaft connecting portion 2a is provided with two counterbored holes 121 and 121 at the end facing the convex portion 123. The counterbored holes 121 and 121 are respectively connected to the axis of the output shaft connecting portion 2a. It is provided in parallel.

  The bit connection portion 2b is provided on the axis thereof so that a fitting portion 130 fitted to the tip end portion of the bit 6 and a fitting hole 134 through which the insulating shaft 150 can be inserted communicate with each other. The bit connecting portion 2b is provided with a protruding portion 135 at the end thereof, and two tapped holes 132 and 132 arranged so as to extend from the outer periphery toward the axis. Yes. A pilot hole 132 a that is common to the tap holes 132, 132 passes through the inner wall surface of the fitting portion 130, and is configured such that a retaining pin 160 described later can be inserted from the tap hole 132. Further, the bit connection portion 2b is provided with counterbored holes 131 and 131 at two positions opposite to the convex portion 135. The counterbored holes 131 and 131 are parallel to the axis of the bit connection portion 2b, respectively. Is provided.

  Further, since the output shaft connecting portion 2a and the bit connecting portion 2b are made of metal, the fitting portions 120 and 130 are rotated in contact with the output shaft 5a and the bit 6, respectively. It is hard to wear.

  The insulating connection portion 2c is made of MC nylon (registered trademark) having strong hardness and insulation properties, and concave portions 143 and 145 are formed on both end surfaces thereof to fit the convex portions 123 and 135, respectively. On the other hand, an insertion hole 144 that is aligned with the axis and penetrates the entire length is provided. Further, tapped holes 141 are respectively arranged on both end surfaces of the insulating connecting portion 2c so as to correspond to the counterbored holes 121, 121, 131, 131. The insertion holes 144 are formed at positions that do not interfere with each other.

  The insulating shaft 150 has the same characteristics as the material of the insulating connecting portion 2c, and its shape is a solid axis. The insulating shaft 150 is set to have a diameter that is substantially the same as the insertion hole 144, the fitting hole 124, and the fitting hole 134, but slightly longer than the entire length of the insulating connecting portion 2c. Is done.

  The bit 6 is provided with a fitting hole (not shown) for securely engaging with the nut and is magnetized, so that the nut can be held by suction. Further, a hole 6b through which the retaining pin 160 can be inserted is provided at one end of the bit 6, and the retaining pin 160 can be inserted into one end of the output shaft 5a as well as the bit 6. A hole 5b is provided.

  By the way, in order to prevent the output shaft 5a and the bit 6 from coming off from the output shaft connecting portion 2a and the bit connecting portion 2b in the axial direction, the retaining pins 160 and 160 are inserted from the tap holes 122 and 132, respectively. Has been. Further, set screws 161 are screwed into the tap holes 122, 122, 132, 132 so as to close both end faces of the retaining pins 160, 160, respectively.

  That is, the shaft coupling 2 is characterized in that since the insulating connecting portion 2c is disposed in the middle, the output shaft 5a and the bit 6 can be integrally connected while being insulated. Further, since the insulating connecting portion 2c is made of the insulating property and the hard hardness, there is also a feature that high torque can be reliably transmitted while having electrical insulating performance even with high torque. Further, since the shaft coupling 2 incorporates the insulating shaft 150 that matches the respective axes of the output shaft connecting portion 2a and the bit connecting portion 2b, the axes of the output shaft 5a and the bit 6 are always matched. There is also a feature that can suppress the sound or vibration generated during rotation

  On the other hand, the reciprocating means 20 includes a ball screw 17 extending parallel to the axis of the screw fastening tool unit 10, a frame 16 that rotatably supports both ends of the ball screw 17, and the frame 16 fixed to the frame 16. A lifting drive motor 15 and an output shaft 15 a of the lifting drive motor 15 are connected to one end of the ball screw 17. Also. The ball screw 17 is provided with a movable member 18 that meshes with the threaded portion and moves up and down in response to the rotation of the ball screw 17 and a mounting plate 19 that is fixed to the movable member 18 and to which the screw tightening tool unit 10 can be attached. ing. A guide plate 12 that guides the outer periphery of the bit 6 is fixed to the lower portion of the frame 16.

  The elevating drive motor 15 is connected to an elevating control device (not shown), and rotates at a predetermined rotational speed in response to a command from the elevating control device, so that the ball screw 17 connected to the elevating drive motor 15 is connected to the ball screw 17. Configured to add rotation. The elevating drive motor 15 is connected to the ground level GND, and is configured to be able to ground static electricity charged in the elevating drive motor 15.

  The guide plate 12 is formed with a guide hole (not shown) having an inner diameter substantially equal to the outer diameter of the bit 6, and the bit 6 can be inserted into the guide hole. In addition, since the guide plate 12 has a property that the material has insulating properties and extremely high wear resistance due to sliding with metal, each of the guide plates 12 suppresses vibration during rotation of the bit 6, The bit 6 and the frame 16 can be completely insulated.

  Therefore, in the automatic screw tightening machine 1, the bit 6 and the output shaft 5 a are insulated by the shaft coupling 2, and the bit 6 and the frame 16 are insulated by the guide plate 12. For this reason, the bit 6 and the output shaft 15a are also insulated.

  As shown in FIG. 2, a chuck unit 30 that can temporarily hold the nut may be attached to the guide plate 12. The chuck unit 30 includes a chuck body 31 in which a hole (not shown) through which the bit 6 can be inserted is disposed, and chuck claws 32 that are disposed at the tip of the chuck body 31 and are swingably attached. 33 and a pipe 34 that protrudes from the chuck body 31 and has a passage hole (not shown) through which the nut can pass. The chuck body 31 is fixed so as to be suspended from the guide plate 12 and is configured to allow the bit 6 guided by the guide plate 12 to be inserted therethrough. On the other hand, the chuck claws 32 and 33 are arranged opposite to each other, and are always closed by springs (not shown) arranged therein. Further, the inside of the chuck claws 32 and 33 is configured to hold one of the nuts in a closed state, and communicates with a passage hole of a pipe 34 described later. Further, the closed chuck claws 32 and 33 are configured to swing in the direction of being opened by being pushed by the tip of the bit 6 when the bit 6 is lowered. The pipe 34 is fixed to the chuck main body 31 and is configured to be able to pass nuts supplied from the tip thereof into the chuck claws 32 and 33. Further, since the pipe 34 is connected to a component supply device (not shown) that can separate and feed the nuts one by one, the nut can be appropriately supplied to the inside of the chuck unit 30. That is, the automatic screw tightening machine 1 provided with the chuck unit 30 has a feature that the nut can be appropriately supplied and continuously tightened in addition to the above-described features.

  Next, the operation of the automatic screw tightening machine 1 of the present invention will be described below. In the automatic screw tightening machine 1 of the present invention, a fastening start command signal is input to the driver control device and the lift control device by an operator (not shown). In response to this, the driver control device sends a rotational drive command to the bit drive motor 5 to rotate the bit 6 at a predetermined rotational speed. At the same time, the lift control device sends a rotation drive command to the lift drive motor 15 to rotate the ball screw 17 at a predetermined rotational speed. Accordingly, the movable member 18 is lowered along the axis of the ball screw 17, and the screw tightening tool unit 10 is lowered together with the mounting plate 19. At this time, the bit 6 is fastened to the guide plate 12 that guides the outer periphery of the bit 6 and slides downward to fit the nut to the work.

  Here, a description will be given of a use example in which two automatic screwing machines 1 of the present invention are used, and the nut is simultaneously fastened to both the positive and negative electrodes 51 and 52 having a predetermined electric potential. In this description, the conventional automatic screwing machines 100 and 100 of FIG. 7 are replaced with the automatic screwing machines 1 and 1 of the present invention and will be described below.

  In response to the fastening start command signal issued by the operator's operation, the two automatic screwing machines 1 and 1 adsorb the nuts to the tips of the rotating bits 6 and 6, respectively, and descend simultaneously. . As a result, the bits 6 and 6 screw nuts into the electrodes 51 and 52, respectively. At this time, when the nut comes into contact with the electrodes 51 and 52, electricity stored in the work 50 is charged to the nut and the bits 6 and 6, respectively. However, since the electricity is not charged to components other than the bits 6 and 6 by the shaft couplings 2 and 2 and the guide plates 12 and 12, the bit drive motors 5 and 5 and the reciprocating means 20 and 20 Are not communicated to each.

  As described above, the automatic screw tightening machine 1 of the present invention insulates the guide plate 12 made of an insulating material for guiding the outer periphery of the bit 6 and the output shaft 5a of the bit 6 and the bit drive motor 5 from each other. Since it comprises the shaft coupling 2 made of an insulating material to be connected, even if electricity is supplied to the bit 6, it is not transmitted to components other than the bit 6. Therefore, the electricity is not transmitted from the bit 6 to the inside of the bit drive motor 5 by the shaft coupling 2 and is not transmitted to the inside of the elevating drive motor 15 by the guide plate 12. Therefore, the screw tightening machine 1 of the present invention has an advantage that the bit drive motor 5 and the lift drive motor 15 are not damaged by energization of the bit 6.

  As described in the present embodiment, the chuck unit 30 may be attached to the guide plate 12. In this case, the automatic screw tightening machine 1 appropriately supplies the nut to the inside of the chuck unit 30. In addition, since the fastening can be performed continuously, there is an advantage that the fastening work can be performed in a reliable and highly efficient state. Also, by replacing the conventional automatic screwing machines 100 and 100 of FIG. 7 with the automatic screwing machines 1 and 1 of the present invention, the components other than the bit 6 to the bit 6 can be completely replaced as described above. Since it is insulated, the work 50 will not be short-circuited even if nuts are simultaneously fastened to the electrodes 51 and 52 of the work 50 such as a storage battery that could not be fastened. Therefore, the automatic screw tightening machines 1 and 1 of the present invention can simultaneously fasten a plurality of nuts to the workpiece 50, so that the fastening time can be minimized. Further, since the frame 16 of the reciprocating means 20 is insulated by the shaft coupling 2 and the guide plate 12 even when electricity of the work 50 is transmitted to the bit 6, the frame 16 is fixed to and abutted on the frame 16. Neither the column 92 nor the base 91 is energized. Therefore, even if an operator (not shown) touches the column 92 and the base 91, there is an advantage that the operator can safely perform the fastening operation without being electrocuted.

DESCRIPTION OF SYMBOLS 1 Automatic screwing machine 2 Shaft coupling 2a Output shaft connection part 2b Bit connection part 2c Insulation connection part 5 Bit drive motor 5a Output shaft 6 Bit 10 Screw tightening tool unit 12 Guide plate 15 Lift drive motor 15a Output shaft 16 Frame 17 Ball screw 18 Movable member 19 Mounting plate 20 Reciprocating means 30 Chuck unit 31 Chuck body 32 Chuck claw 33 Chuck claw 34 Pipe 50 Work 51 Electrode (fastening location)
52 Electrode (Fastening point)
70 Screw tightening tool unit (conventional product)
71 Housing 72 Conductive mechanism 73 Drive shaft 74 Slip ring 75 Bearing 76 Bit 77 Insulating member 78 Shaft coupling (conventional product)
80 Reciprocating means (conventional product)
91 Base 92 Column 100 Automatic screwing machine (Conventional product)
112 Guide plate GND Ground level

Claims (3)

A screw tightening tool unit including a shaft coupling capable of transmitting rotation by integrally connecting an output shaft of a rotational drive source and a bit engaging a desired part, and a reciprocating drive source including a guide plate through which the bit can be inserted In an automatic screw tightening machine comprising reciprocating means enabling reciprocating movement of the screw tightening tool unit by driving
The shaft coupling and the guide plate are each provided with an insulating property, and are configured so as not to pass electricity charged to the bit to the rotary drive source and the reciprocating drive source, respectively.   A pair of chuck claws provided with holding parts capable of holding the components supplied as appropriate, a chuck body that supports the chuck claws so as to be swingable, and allows the insertion of the bit and the passage of the parts, respectively; The automatic screw tightening machine according to claim 1, wherein a chuck unit including a pipe connected to the chuck body and having a passage hole through which the component can pass is fixed to the guide plate. .   3. The automatic screw tightening machine according to claim 1, comprising a plurality of the screw tightening tool units and the guide plates and configured to be capable of simultaneous tightening at a plurality of locations.

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