JP6114811B1 - Screwing machine - Google Patents

Abstract

An object of the present invention is to provide an inexpensive screw tightening machine that can cope with screw tightening work on a workpiece having many steps. A bit rotation motor capable of driving a bit B engageable with a screw S to be screwed into a workpiece W at a predetermined rotational speed, and a plate 21 having the bit rotation motor 10 fixed to the upper portion of a bit B Reciprocating means 20 that can reciprocate in the extending direction, a slide housing 30 that is fixed to the lower portion of the plate 21 and through which the bit B is inserted, and a screw guide that is inserted through the bit B and is slidable in the slide housing 30 50 and a stopper means 40 configured to connect a stopper member 41 arranged around the axis of the screw guide 50 and stop the movement of the screw guide 50 by pressing the stopper member 41. Further, the screw guide 50 is connected to a relative moving means 60 that slides so as to include the tip of the bit B. [Selection] Figure 1

Description

  The present invention relates to a screw fastening machine for fastening a screw to a workpiece.

  As shown in Patent Document 1, a conventional screw tightening machine includes a screw tightening tool having a bit that engages with a screw, and a reciprocating means that supports the screw tightening tool so as to reciprocate in the axial direction of the bit. Be prepared. The screw tightening tool includes a bit rotation motor that can be driven to rotate at a predetermined speed by connecting the bit, a screw guide that can be inserted through the bit and can suck the screw, and the screw guide in the axial direction of the bit. The slide housing includes a slide housing that is slidably supported, and a spring that is disposed in the slide housing and constantly biases the screw guide toward the distal end side of the bit. The reciprocating means is configured to be capable of reciprocating so that the bit has a preset thrust.

  Further, the conventional screw tightening machine includes a chuck unit that can hold the screw by suspending the chuck, and the chuck unit includes a chuck main body through which the screw guide can be inserted, and a swing attached to the chuck main body. It comprises a free pair of chuck claws. The chuck claws are always urged so as to be in a closed state, and are configured to be able to suspend and hold a screw supplied from a screw feeder in the closed state.

  In the conventional screw tightening machine configured as described above, when the tip of the screw guide reciprocated by the reciprocating means abuts against the chuck claw in a closed state, the chuck claw swings in the opening direction. As a result, the screw guide moves in the direction approaching the workpiece together with the bit contained therein and comes into contact with the surface of the workpiece, so that the spring is bent in the compressing direction. Therefore, the bit starts relative movement with respect to the screw guide that has come into contact with the workpiece and stopped, and presses the screw held in the screw guide with a predetermined thrust to tighten the screw on the workpiece.

  Further, the conventional screw tightening machine shown in Patent Document 2 is configured by arranging stopper means above the chuck unit, and this stopper means abuts the screw guide reciprocated by the reciprocating means against the surface of the workpiece. It is configured to be able to stop before letting it go. Accordingly, the tip of the screw guide and the surface of the work do not come into contact with each other, so that the work is not damaged.

  In addition, the conventional screw tightening machine shown in Patent Document 3 is configured such that the reciprocation of the screw guide and the bit can be individually driven and controlled, and the plate in which the screw guide is fixed extends in the direction in which the bit extends. A reciprocating means capable of reciprocating to and from, a bit reciprocating means for reciprocating only the bit disposed on the plate, and a control device for controlling the reciprocating means and the bit reciprocating means, respectively. Each of the reciprocating means and the bit reciprocating means comprises an AC servomotor that can be driven to rotate at a predetermined rotational speed and rotational angle, and these two AC servomotors are connected to the control device, respectively. Yes. Thus, the conventional screw tightening machine shown in Patent Document 3 drives and controls the reciprocating means to move the screw guide and the bit integrally to a predetermined position, and then drives and controls the bit reciprocating means. Only the bit can be moved further to a predetermined position. Therefore, the conventional screw tightening machine shown in Patent Document 3 can arbitrarily set the stop position of the screw guide, and therefore has a feature that it can cope with screw tightening work on a workpiece having a plurality of steps.

Japanese Patent No. 5711550 JP 2000-190142 A Japanese Unexamined Patent Publication No. 2015-20245

  First, since each of the conventional screw tightening machines described above includes a chuck unit, it is necessary to push open a chuck claw that is closed by the tip of a moving screw guide. If the spring constant of the spring is low, the screw guide cannot be swung in the opening direction even if it comes into contact with the closed chuck claw, and the screw guide remains in this position and the spring starts to bend. Since the bit starts to move relative to the screw guide as the spring starts to bend, the head of the screw sucked into the screw guide is pressed against the chuck claw while exhibiting the set thrust of the reciprocating means. . Thereby, the chuck claw in the closed state is opened by the head portion of the screw protruding from the tip of the screw guide, and the screw is dropped on the workpiece. That is, the conventional screw tightening machine has a problem that the screw guide is ejected when the screw guide passes through the chuck unit.

  In order to solve this problem, it is conceivable to set the spring constant of the spring high. However, in this case, during the period from when the screw guide comes into contact with the workpiece until the completion of screw tightening, a high pressing force is applied to the workpiece with a high repulsive force of the spring and a set thrust of the bit applied by the reciprocating means. Will be added. In other words, since the conventional screw tightening machine applies the above-described high pressing force to the workpiece, there is also a problem that it cannot cope with a screw tightening operation such as a resin workpiece weak against the pressing force.

  Further, the conventional screw tightening machine shown in Patent Document 2 is stopped by the stopper means before the tip of the screw guide abuts against the surface of the workpiece, so that thrust is not applied to the workpiece more than necessary. However, there is a problem that the stopper means continues to receive a high repulsive force by the spring until the screw tightening is completed. Furthermore, the conventional screw tightening machine shown in Patent Document 2 has to arrange a large number of the stopper means around the axis of the screw guide in order to cope with a work having a multi-stage surface screw tightening point. Therefore, there is a problem that it is difficult to reduce the size and weight.

  Further, the conventional screw tightening machine shown in Patent Document 3 has a problem that it is difficult to reduce the cost because an AC servo motor is disposed in each of the reciprocating means and the bit reciprocating means. Furthermore, since it is necessary to drive and control two AC servo motors, there is a problem that the control becomes complicated.

The present invention has been made in view of the above problems, and a bit rotation motor capable of driving a bit engageable with a screw screwed into a workpiece at a predetermined rotational speed, and the bit rotation motor fixed to the upper part. A reciprocating means capable of reciprocating in the extending direction of the bit, a slide housing fixed to the lower part of the plate and passing through the bit, and a slide housing through which the bit is inserted and slidable in the slide housing. In a screw tightening machine comprising a screw guide and a stopper member that is formed by connecting a stopper member arranged around the axis of the screw guide, and stopper means that presses the stopper member and can stop the movement of the screw guide. become comprises a relative movement means for relatively moving the screw guide relative to the bit, the relative movement means, pressure By supplying air to the inside of the slide housing and said formed Rukoto. The screw guide is constantly engaged with an elastic member that urges the bit toward the bit rotation motor to project the bit, and the relative movement means is in a direction against the urging force of the elastic member. It is preferable that the screw guide is slid and the bit is relatively moved into the screw guide. Further, the relative movement means, the direct-acting cylinder that reciprocates in the direction of extension of said bit by supplying compressed air, may be constructed by connecting the screw guide the linear motion cylinder. Further, the relative moving means, the stopper means, and the reciprocating moving means are connected to a control device that controls driving of each, and the control device operates the relative moving means to move the tip of the screw guide to the After being positioned forward of the bit, the reciprocating means is operated to move the screw guide and the bit integrally, and before the tip of the screw guide contacts the workpiece based on the positional information of the reciprocating means. It is preferable that the stopper means is operated so as to stop the movement of the screw guide.

  Since the screw tightening machine according to the present invention includes relative movement means that can slide so as to press the screw guide against the tip end side of the bit, even if an external force is applied to the screw guide that passes through the chuck unit, the external force is only overcome. The screw guide exerts the pressing force of. Thus, the screw tightening machine of the present invention can overcome the external force generated when the screw guide passes through the chuck unit and is not easily pushed back, so that the screw guide can pass through the chuck unit in a state where the screw head is housed in the screw guide. . Therefore, there is an advantage that it is possible to reduce the occurrence of a problem that the screw is flipped off from the chuck unit as in the prior art.

  In the screw tightening machine of the present invention, the screw guide is constantly urged toward the bit rotation motor side to project the bit, and the screw guide is slid in a direction against the urging force of the elastic member. Relative movement means. Thereby, immediately after stopping the movement of the screw guide by the stopper means, the moving force of the screw guide can be reduced to the urging force of the elastic member. Therefore, the screw tightening machine of the present invention has an advantage that the life of the stopper means can be extended as compared with the prior art without applying an excessive load to the stopper means in a state where the screw guide is stopped by the stopper means.

  Further, since the screw tightening machine of the present invention can realize the sliding operation (the above-mentioned relative movement) of the screw guide by switching the compressed air, two AC servo motors as in the conventional screw tightening machine disclosed in Patent Document 3. There is also an advantage that it can be made cheaper than the configuration provided with. In addition, since the screw tightening machine of the present invention is configured to supply the relative moving means to the inside of the slide housing, the screw tightening machine can be reduced in size and weight compared to a configuration including two AC servo motors. There is also an advantage of becoming.

It is a schematic structure figure showing one embodiment of a screw fastening machine concerning the present invention. FIG. 2 is a partially cutaway cross-sectional view for explaining the operation of FIG. 1, (a) is an in-situ state, (b) is a state in which compressed air is supplied into a slide housing, and (c) is a reciprocating means. (D) shows a state in which the screw guide is stopped by operating the stopper means, and (e) shows a state in which the screw is fastened to the workpiece by a bit. It is. FIG. 5 is a partially cutaway cross-sectional view showing a main part of another embodiment according to the present invention, in which (a) shows a compression spring instead of the tension spring of FIG. 1, and (b) supplies compressed air into the slide housing. In the configuration, (c) uses a linear motion cylinder.

  The screw tightening machine of the present invention will be described below with reference to FIGS. The screw tightening machine 1 according to the present invention is a reciprocating motor capable of moving up and down a bit rotating motor 10 connected to a bit B engageable with a screw S to be fastened to a workpiece W and a plate 21 to which the bit rotating motor 10 is fixed. The moving means 20, a screw guide 50 inserted through the bit B, and a slide housing 30 that slidably supports the screw guide 50 are provided.

  The bit rotation motor 10 includes an output shaft 10c to which the bit B is connected, a motor unit 10b that drives the output shaft 10c to rotate at a predetermined rotational speed and torque, and an output shaft disposed above the motor unit 10b. It is comprised from the encoder part 10a which can transmit the pulse signal according to the rotation angle of 10c.

  The reciprocating means 20 includes an AC servo motor (hereinafter referred to as a lifting motor 22) having the same configuration as the bit rotation motor 10, a motor fixing plate 25 to which the lifting motor 22 is fixed, and the motor fixing plate 25. A chuck fixing plate 26 arranged in parallel downward, a connecting plate 27 for connecting the motor fixing plate 25 and the chuck fixing plate 26, and a ball screw shaft connected to an output shaft (not shown) of the elevating motor 22 23, a movable nut 24 that is slidably engaged with the ball screw shaft 23 and rotates along the ball screw shaft 23, and the plate 21 that rotatably supports the movable nut 24. . The elevating motor 22 is configured to rotate the ball screw shaft 23 at a predetermined rotational speed and torque, and a pulse signal corresponding to the rotation angle of the ball screw shaft 23 disposed above the motor portion 22b. And an encoder unit 22a capable of transmitting. The reciprocating means 20 can be moved over the workpiece W by the robot arm 110 to which the connecting plate 27 is connected. The reciprocating means 20 configured as described above allows the bit B to reciprocate along the axis thereof because the plate 21 can move up and down along the ball screw shaft 23.

  The screw guide 50 is integrally provided with a flange portion 50a formed at one end thereof and a shaft portion 50b having a smaller diameter than the flange portion 50a. The screw guide 50 includes an insertion hole 50c through which the bit B can be inserted in the axial direction thereof, and a ventilation hole 50d having a diameter larger than that of the insertion hole 50c. 70.

  The slide housing 30 is configured such that the flange portion 50a of the screw guide 50 is slidably supported along the bit B, and the shaft portion 50b is always protruded downward from one end thereof. It is attached.

  Further, the screw tightening machine 1 according to the present invention includes a stopper means 40 capable of pressing the outer periphery of the screw guide 50, a relative moving means 60 movable to move the screw guide 50 relative to the bit B, and fastening. A screw feeder 90 that can store a large number of screws S, which are examples of components, and can pneumatically feed them one by one, and a chuck unit 80 that suspends and holds the head of the screw S that is pneumatically fed by the screw feeder 90. A suction means 70 capable of sucking air from the tip of the screw guide 50 and a control means 100 capable of controlling each device such as the reciprocating movement means 20, the stopper means 40, the relative movement means 60, and the like.

  The stopper means 40 is attached to the reciprocating means 20 and includes a stopper member 41 arranged around the shaft 50b of the screw guide 50. As shown in FIG. 2, the stopper member 41 is configured to reciprocate in a direction orthogonal to the direction in which the screw guide 50 extends, and the screw guide 50 is positioned immediately before the tip of the screw guide 50 contacts the workpiece W. The outer periphery of 50 is comprised so that clamping is possible.

  The relative moving means 60 includes an air tank 63 filled with compressed air of a predetermined pressure, and an electromagnetic valve 61a connected to the air tank 63 and capable of switching between cutoff and supply of the compressed air. The screw guide 50 is slidable toward the tip end side of the bit B by compressed air supplied through the air.

  In the embodiment shown in FIGS. 1 and 2, the relative movement means 60 has the electromagnetic valve 61 a connected to the slide housing 30 and receives the command from the control means 100 to transfer the compressed air to the slide housing. 30 is configured so as to be supplied to the inside. The relative moving means 60 includes a tension spring 62a which is an example of an elastic member connecting the slide housing 30 and the screw guide 50. As a result, the screw guide 50 moves relative to the bit B and encloses the bit B because the flange portion 50a is pressed downward by the pressure of the compressed air supplied into the slide housing 30. . Further, since the compressed air is not always supplied into the slide housing in the screw guide 50, the flange 50a is pulled upward by the urging force of the tension spring 62a, and the bit B protrudes from the tip thereof. Yes.

  Moreover, the relative movement means 60 of another embodiment shown to Fig.3 (a) makes the said tension spring 62a the compression spring 62b which can be elastically deformed to a compression direction, and this compression spring 62b is always on the lower surface of the said collar part 50a. It arrange | positions in the said slide housing 30 so that it may contact | abut. 3A is pressed in the direction in which the compression spring 62b is compressed by the flange portion 50a of the screw guide 50 that moves downward due to the pressure of the compressed air.

  Further, the relative movement means 60 of another embodiment shown in FIG. 3B is configured not to include the above-described elastic member, and includes electromagnetic valves 61b respectively connected to the upper and lower portions of the slide housing 30. . The electromagnetic valve 61b normally supplies the compressed air to the lower part of the slide housing 30, while enabling a path for releasing the compressed air in the slide housing 30 from the upper side of the slide housing 30 to the outside. In response to this command, the above-described route can be switched in the reverse direction.

  3 (c) includes a direct acting cylinder 65 connected to the electromagnetic valve 61b, a movable portion 65a of the direct acting cylinder 65, and a shaft portion of the screw guide 50. And a connecting member 66 to which 50b is connected. The linear cylinder 65 is attached to the lower surface of the plate 21 in the same manner as the slide housing 30, and the movable portion 65a is normally drawn into the main body. Therefore, the linear cylinder 65 extends in the direction in which the movable member 65a extends in response to the operation of the electromagnetic valve 61b, so that the screw guide 50 connected thereto can be moved up and down along the bit B.

  As described above, the relative movement means 60 in the screw tightening machine 1 of the present invention is configured such that the screw guide 50 can be relatively moved with respect to the bit B by switching the compressed air path of the electromagnetic valve 61a or the electromagnetic valve 61b. .

  The chuck unit 80 includes a chuck main body 81 that is disposed below the chuck fixing plate 26 and can be inserted through the screw guide 50, and a pair of chuck claws 82 (82) that are swingably disposed at the tip of the chuck main body 81. ), A joint 83 fixed to the chuck body 81 and capable of passing through the screw S, and the screw S that has passed through the joint 83 is guided to the chuck pawl 82 and is pushed by the tip of the screw guide 50 to swing. And a swing pipe 84.

  Each of the chuck claws 82 (82) is urged by a urging member (not shown) so as to be always closed, and is configured to swing in the opening direction when the screw guide 50 passes therethrough. The When the chuck claws 82 (82) are in the closed state, the chuck claws 82 (82) can be suspended by supporting the heads of the screws S and partially projecting the tips of the screws S from the chuck claws 82. Next, the swing pipe 84 is normally biased by a biasing member (not shown) so as to communicate the joint 83 and the closed chuck claw 82, and comes into contact with the tip or outer periphery of the screw guide 50. It is configured to be pivotable.

  The suction means 70 includes an electromagnetic valve 71 connected to the air tank 63 and having the same structure as the electromagnetic valve 61a, and a convam 72 connecting the electromagnetic valve 71 and the vent hole 50d of the screw guide 50. The convam 72 is configured to suck air from the tip of the screw guide 50 when supplied with compressed air from the electromagnetic valve 71.

  The operation of the screw tightening machine 1 configured as described above will be described with reference to FIGS. 1 and 2A to 2E. In the screw tightening machine 1 of the present invention, after the robot arm 110 moves above a predetermined screw tightening point, the control means 100 drives the bit rotation motor 10 and the lifting motor 22 to rotate at a preset rotation speed and torque, respectively. At the same time, the solenoid valve 61a and the solenoid valve 71 are also operated. As a result, the screw guide 50 moves from the position shown in FIG. 2A to the position shown in FIG. 2B so that the tip of the bit B is included and retracted to the back. At this time, the tension spring 62a is extended to a predetermined length, and the screw guide 50 is being lifted upward. However, the screw guide 50 is moved downward by compressed air having a pressure that exceeds the lifting force of the tension spring 62a. Since it is pressed, the bit B is kept pulled as described above.

  Next, when the screw guide 50 and the bit B are integrally lowered, the swing pipe 84 and the chuck claw 82 (82) are in contact with the tip and outer periphery of the screw guide 50 in order as shown in FIG. As a result, the swing pipe 84 turns, and the chuck pawl 82 (82) swings in the opening direction, resulting in the state shown in FIG. That is, the screw guide 50 receives the external force of the swing pipe 84 and the chuck claw 82 (82) when the swing pipe 84 is swung and swinged in the direction to open the chuck claw 82 (82). Is pushed in the direction to be pushed back. However, since the compressed air supplied into the slide housing 30 has a pressure that sufficiently overcomes the aforementioned external force, the screw guide 50 may move relative to the chuck unit 80 as in the prior art. No.

  Further, when the swing pipe 84 is turned by the screw guide 50, the screw S suspended from the chuck claw 82 is sucked into the screw guide 50 by the negative pressure generated by the convam 72 connected to the electromagnetic valve 71. Thereafter, the screw guide 50 and the bit B are lowered to the position shown in FIG. Here, since the stopper means 40 is actuated, the stopper member 41 clamps the outer periphery of the screw guide 50 being lowered, and restricts the lowering of the screw guide 50 alone.

  Note that the control means 100 is the lift position of the plate 21 calculated by the control means 100 based on the pulse signal transmitted from the lift motor 22 and the preset lead angle of the ball screw shaft 23, that is, The tip position of the bit B is calculated each time, and the tip position of the calculated bit B is used as the operation timing of the stopper means 40. This operation timing is set in advance for each screw tightening point, and is registered in the control means 100 so that the tip position of the screw guide 50 is just before contacting the upper surface of the workpiece W.

  Further, after confirming the operation of the stopper means 40, the control means 100 sends a command to the electromagnetic valve 61 a to stop the supply of compressed air into the slide housing 30. Therefore, since the stopper means 40 can hold the screw guide 50 in a state where only the urging force of the tension spring 62a is received, the stopper means 40 receives only a relatively weak pressing force excluding the influence of the compressed air. The screw tightening machine 1 shown in FIG. 3 (a) has a structure that is different from the screw tightening machine shown in FIG. 1 and FIG. Structure.

  Since the lifting motor 22 continues to rotate after the movement of the screw guide 50 is restricted by the stopper means 40 described above, only the bit B rotating by driving the bit rotating motor 10 is further lowered, The screw S is pushed out from the tip of the screw guide 50 by a predetermined thrust. As a result, the screw S is fastened by the bit B that comes into contact with the workpiece W and exhibits predetermined thrust and rotational force.

DESCRIPTION OF SYMBOLS 1 Screw fastening machine 20 Reciprocating means 22 Lifting motor 30 Slide housing 40 Stopper means 50 Screw guide 60 Relative moving means 61a Solenoid valve 61b Solenoid valve 62a Tension spring 62b Compression spring 65 Linear motion cylinder 100 Control means

Claims (4)

A bit rotation motor capable of driving a bit engageable with a screw to be screwed into a workpiece at a predetermined rotation speed, and a reciprocating means capable of reciprocating in a direction in which the bit extends a plate having the bit rotation motor fixed thereon. A slide housing fixed to the lower part of the plate and inserted through the bit, a screw guide inserted through the bit and slidably disposed in the slide housing, and arranged around the axis of the screw guide In a screw tightening machine provided with stopper means that is configured by connecting a stopper member and pressing the stopper member to stop the movement of the screw guide,
Comprising a relative movement means for moving the screw guide relative to the bit ;
The relative movement means, screwing machine the compressed air is supplied to the inside of the slide housing and said formed Rukoto. The screw guide is always engaged with an elastic member that urges the bit guide to the bit rotation motor side to project the bit,
The screw tightening according to claim 1, wherein the relative moving means slides the screw guide in a direction against the urging force of the elastic member, and relatively moves the bit into the screw guide. Machine.   The said relative movement means is a linear motion cylinder that reciprocates in the extending direction of the bit by supplying compressed air, and the screw guide is connected to the linear motion cylinder. The screw tightening machine according to claim 2. The relative moving means, the stopper means, and the reciprocating moving means are connected to a control device that controls driving of each,
The control device operates the relative movement means to position the tip of the screw guide forward of the bit, and then operates the reciprocating movement means to move the screw guide and the bit integrally and reciprocate. 2. The control according to claim 1, wherein the stopper means is operated to stop the movement of the screw guide before the tip of the screw guide comes into contact with the workpiece based on position information of the means. 4. The screw tightening machine according to any one of 3 .

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