JP3820061B2 - Automatic screwing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic screw tightening machine that automatically replaces a screw tightening tool in response to a plurality of types of screws having different head shapes, drive hole shapes, and the like.
[0002]
[Prior art]
Conventionally, when a screw is fastened to a workpiece, an automatic screw tightening machine 50 as shown in FIG. 7 is used. This automatic screw tightening machine 50 has a structure in which a screw tightening tool 53 is connected to an output shaft 52 that rotates by receiving the drive of a motor 51 so as to be detachable and integrally rotatable. In the work station, it is used by connecting it to a robot apparatus such as an articulated robot or by connecting it to a balancer unit 60 as shown in FIG. The balancer unit 60 winds a wire 61 that suspends the automatic screw tightening machine 50 around a rotary reel 62, and attaches the rotary reel 62 in a rotational direction in which the wire 61 is wound by a biasing means (not shown) such as a string spring. The automatic screw tightening machine 50 is suspended in the air and is used by being pulled to the working position when necessary.
[0003]
[Problems to be solved by the invention]
However, in the above-described conventional automatic screw tightening machine, for example, when a plurality of types of screws must be tightened on one work, or when the work is frequently changed and the tightening screw frequently changes, each screw is Several automatic screwing machines with corresponding screwing bits had to be prepared and used separately. Therefore, when a robotic device is used, equipment such as an auto tool changer is also required, which causes problems such as a complicated structure and expensive equipment, and a large installation space. It was. In addition, when using a balancer unit, it is necessary to distinguish between the automatic screw-clamping machines that are suspended, and the one that matches the screw that the operator tightens at any time, which increases the work loss time. For example, when it is necessary to use different screw tightening tools that do not differ greatly in shape, such as a driver bit with a different identification number, the screw drive is driven by screwing them up. Problems such as damaging the holes occurred.
[0004]
[Means for Solving the Problems]
The present invention was created in view of the above problems, and an object of the present invention is to provide an automatic screw tightening machine that can handle a plurality of types of screws without using a plurality of automatic screw tighteners. It is.
[0005]
In order to achieve the above object, the present invention provides an output shaft that is rotatable by being driven by a rotational drive source, and a rotation transmission shaft that is disposed so as to be able to reciprocate while maintaining a rotatable state integrally with the output shaft. An operation means for operating the rotation transmission shaft to reciprocate, and a main drive which is arranged so as to be coupled to and separated from the rotation transmission shaft along with the reciprocation of the rotation transmission shaft and which can rotate integrally with the rotation transmission shaft when coupled. A bevel gear, a driven bevel gear that is always meshed with the driven bevel gear, a turret head that can rotate integrally with the driven bevel gear, and a turret head that is disposed at the predetermined position along with the rotation of the turret head. and a plurality of screwing tools which are configured such that the rotation transmission shaft away from the main driving bevel gear is connected at a position, the main A taper hole is formed in one of the bevel gear and the rotation transmission shaft, and a taper shaft that can match the taper hole is formed in the other. The taper hole and the taper shaft are formed by reciprocating the rotation transmission shaft. The main bevel gear and the rotation transmission shaft are coupled and separated without being phase-matched when they are matched and separated .
[0007]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a first embodiment of the invention will be described with reference to the drawings. 1 to 3, reference numeral 1 denotes an automatic screw tightening machine according to a first embodiment of the present invention, which is a movable part (not shown) of a robot (not shown) such as a well-known articulated robot or a Cartesian coordinate robot. A base member 2 that can be attached to the base member 2 is provided, and a driver tool 4 having an AC servo motor 4a, which is an example of a rotational drive source, is installed on the base member 2. The driver tool 4 has an output shaft 4b that rotates by driving of the AC servomotor 4a, and a rotation transmission switching mechanism 5 is connected to the output shaft 4b. The driver tool 4 includes a known rotary encoder 4c, and is configured so that the rotation angle of the output shaft 4b can be detected by the rotary encoder 4c.
[0008]
The rotation transmission switching mechanism 5 has an air cylinder 6 attached to the base member 2. A slide gear unit is connected to a piston rod 6 a (hereinafter simply referred to as a rod 6 a) of the air cylinder 6 via an operation arm 7. 8 is connected. The air cylinder 6 includes a lower limit sensor 6b that turns on when the rod 6a is extended, and an upper limit sensor 6c that turns on when the rod 6a is contracted. The slide gear unit 8 is disposed in a housing 9 attached to the lower portion of the base member 2, and a slide liner 10 disposed so as to be slidable along a vertical hole 9 a of the housing 9. The rotation transmission shaft 11 is rotatably arranged on the slide liner 10, and a main driving bevel gear 12 is integrally attached to the rotation transmission shaft 11. In the first embodiment, the air cylinder 6 and the operation arm 7 correspond to operation means.
[0009]
An upper portion of the rotation transmission shaft 11 of the slide gear unit 8 is formed in a rectangular column portion 11 a having a substantially quadrangular cross section. The rectangular column portion 11 a is a square hole 4 d formed in the output shaft 4 b of the driver tool 4. Are slidably fitted to each other and can be rotated integrally with the output shaft 4b. The lower portion of the rotation transmission shaft 11 is formed in a spline portion 11b in which a large number of spline grooves are formed. The spline portion 11b can be fitted in a spline drive hole 20a formed in the connecting shaft 20 described later. It is configured.
[0010]
On the other hand, a driven gear shaft 13 is rotatably disposed in an inclined hole 9b formed obliquely communicating with the vertical hole 9a of the housing 9, and one end of the driven gear shaft 13 is connected to the main driving gear. The driven bevel gear 14 meshingly coupled to the gear 12 is connected to rotate integrally . Further , a mortar-like turret head 15 having an external truncated cone shape is attached to the other end of the driven gear shaft 13, and each turret head 15 is screwed into a position that divides the conical surface into three equal parts. Fastening tools 16a, 16b, and 16c are attached.
[0011]
The screw tightening tools 16a, 16b, and 16c are respectively coupled to a coupling 17 attached to the turret head 15, a liner 18 disposed on the coupling 17, and slidable and rotatable along the liner 18. Each of the slide shafts 19, the connecting shaft 20 fitted to the slide shaft 19, and a compression spring 21 disposed between the connecting shaft 20 and the slide shaft 19. Sockets 22, 23, and 24 are integrally connected to the tip of the shaft 19, respectively.
[0012]
The connecting shaft 20 is rotatably fitted to a hole 15a formed through the conical surface of the turret head 15 via a bearing, whereby a spline driving hole 20a formed at the upper end of the connecting shaft 20 is It is exposed to the inner conical surface of the turret head 15. Further, the connecting shaft 20 and the slide shaft 19 are connected by fitting a prism 20b formed at the tip of the connecting shaft 20 into a square hole 19a formed at the top of the slide shaft 19, Thus, both the slide shaft 19 and the slide shaft 19 can reciprocate along the connecting shaft 20.
[0013]
The sockets 22, 23, and 24 are each formed with a hexagonal hole that can be engaged with the head of the hexagonal bolt at the tip, and correspond to hexagonal bolts having different names. Incidentally, in this example, the socket 22 is for M6, the socket 23 is for M8, and the socket 24 is for M10.
[0014]
The sockets 22, 23, and 24 are configured so as to be arranged in a vertical posture on the extension of the axis of the driver tool 4 as the turret head 15 rotates, and correspond to the sockets 22, 23, and 24. The turret head 15 is provided with three ball plungers 22a, 23a, and 24a. These plungers 22a, 23a, and 24a are formed in the housing 9 when the corresponding sockets are in the vertical axis posture. The turret head 15 is prevented from rotating by engaging with the engaging hole 9c. The turret head 15 is also provided with three detected members 22b, 23b, 24b (24b not shown) corresponding to the sockets 22, 23, 24, and these detected members 22b, 23b. , 24b are configured to be detected by the proximity sensor 25 disposed in the housing 9 when the corresponding socket is in a vertical posture.
[0015]
The automatic screw tightening machine 1 having the above configuration is arranged at a work station of a conveyor (not shown) in the assembly line, and is temporarily tightened to a work (not shown) conveyed to the work station. Tighten the hexagonal bolt (not shown). When tightening the hexagon bolt, first, the automatic screw tightening machine 1 is moved by the operation of the robot in the state shown in FIGS. 1 and 2, and the socket 22 is positioned above the predetermined hexagon bolt of the workpiece. At this time, if the socket 22 does not fit the hexagon bolt, the socket is rearranged.
[0016]
In order to explain the operation including the rearrangement of the sockets 22, 23, and 24, a case where the socket 23 is arranged on the extension of the axis of the driver tool 4 and the hexagon bolt is tightened will be described below.
[0017]
In this case, first, the AC servomotor 4a of the driver tool 4 is driven in the state shown in FIGS. 1 and 2, and the output shaft 4b is rotated until the rotary encoder 4c counts a predetermined rotation angle. As a result, the rotation transmission shaft 11 and the main drive bevel gear 12 are rotated by a predetermined rotation angle, and the turret head 15 is rotated by a predetermined rotation angle via the driven bevel gear 14 and the driven gear shaft 13. By the rotation of the turret head 15, the socket 23 moves so as to be in a vertical posture on the axis line extension of the driver tool 4. At the same time, the plunger 23 a engages with the engagement hole 9 c to prevent the turret head 15 from rotating, and the detected protrusion 23 b is detected by the proximity sensor 25. The driving of the AC servo motor 4a is stopped when the rotary encoder 4c counts a predetermined rotation angle, and at that time, from the detection signal of the proximity sensor 25, is the socket 23 arranged on the extension of the axis of the driver tool 4? It is confirmed.
[0018]
When the socket 23 is disposed on the extension of the axis of the driver tool 4, the air cylinder 6 subsequently extends the rod 6 a and lowers the slide gear unit 8. As a result, the mesh between the driven bevel gear 12 and the driven bevel gear 14 is released (the slide gear unit 8 is separated from the driven bevel gear 14), and the spline portion 11b of the rotation transmission shaft 11 is connected to the connecting shaft 20 of the screw tightening tool 16b. It fits into the spline drive hole 20a. At this time, the prism portion 11a remains engaged with the square hole 4d of the output shaft 4b, so that the rotation of the output shaft 5b can be transmitted to the socket 23 of the screw tightening tool 16b. In order to fit the spline portion 11b and the spline drive hole 20a, it is necessary to match these phases, so that the rotation transmission shaft 11 is splined after the main bevel gear 12 and the driven bevel gear 14 are disengaged. Until the portion 11b is fitted into the spline drive hole 20a, the AC servomotor 4a is driven to rotate.
[0019]
As described above, when the spline portion 11b is fitted into the spline drive hole portion 20a, the lower limit switch 6b of the air cylinder 6 is turned on, and the robot is actuated again to lower the automatic screw tightening machine 1. As a result, the socket 23 comes into contact with the head of the hexagon bolt, and the slide shaft 19 escapes into the coupling 17 by a predetermined amount against the bias of the compression spring 21.
[0020]
In this state, the automatic screw tightening machine 1 is held, and then the AC servo motor 4a is driven again to rotate the output shaft 4b. The rotation of the output shaft 4 b is transmitted to the socket 23 via the connecting shaft 20 and the slide shaft 19. As a result, the engagement hole of the socket 23 engages with the hexagon bolt head, and rotation transmission is performed to the hexagon bolt so that it can be fastened to the workpiece. At this time, the slide shaft 19 is advanced and returned by the urging of the compression spring 21 as the hexagonal bolt is screwed into the workpiece, so that the socket 23 can follow the screwing of the hexagonal bolt.
[0021]
When the first screw tightening operation is normally completed in this way, the automatic screw tightening machine 1 moves to the next tightening operation point by the operation of the robot, and tightens the next hexagon bolt as described above. At this time, if the name of the hexagon bolt to be tightened is different from the previous one, the air cylinder 6 is actuated to raise the slide gear unit 8 before the tightening operation, and the main driving bevel gear 12 is engaged with the driven bevel gear 13 again. Combine. As a result, the rotation of the output shaft 4b can be transmitted to the turret head 15. Also at this time, the rotation transmission shaft 11 corrects the phase shift between the main driving bevel gear 12 and the driven bevel gear 14, so that the main driving bevel gear 12 meshes with the driven bevel gear 14 after the spline portion 11 b and the spline driving hole 20 a are disengaged. Until the AC servo motor 4a is driven. Note that the engagement of the main drive bevel gear 12 with the driven bevel gear 14 is confirmed by turning on the upper limit sensor 6c of the air cylinder 6. In response to this, the drive of the AC servo motor 4a is immediately stopped.
[0022]
After the slide gear unit 8 is moved up to a position where the main drive bevel gear 12 meshes with the driven bevel gear 14, the socket is rearranged by the same operation as described above, and the hexagon bolt tightening operation is continued. The automatic screw tightening machine 1 goes around the tightening work points on the workpiece in this way, and tightens the hexagon bolts using the corresponding sockets.
[0023]
In the first embodiment described above, the rotation of the rotation transmission shaft 11 is transmitted to the turret head 15 by meshing between the main driving bevel gear 12 and the driven bevel gear 14. The driven bevel gear 14 may be replaced with a friction rotating cone having a friction conical surface, and rotation transmission may be performed by these frictional contacts.
[0024]
Next, a second embodiment of the present invention will be described. 4 to 6, reference numeral 100 denotes an automatic screw tightening machine according to the second embodiment of the present invention, which has the same configuration as the automatic screw tightening machine 1 except for the structure of the rotation transmission switching mechanism and its peripheral parts. Is. Accordingly, here, the same components as those of the automatic screw tightening machine 1 are denoted by the same reference numerals as those described above, and individual descriptions are omitted.
[0025]
A rotation transmission switching mechanism 50 of the automatic screw tightening machine 100 includes an air cylinder 51 attached to the base member 2, and a piston rod 51 a (hereinafter simply referred to as a rod 6 a) of the air cylinder 51 is connected to an operation arm 52. The slide unit 53 is connected via the. In the second embodiment, the air cylinder 51 and the operation arm 52 correspond to the operation means described in the claims .
[0026]
The slide unit 53 is disposed in a housing 9 ′ attached to the lower part of the base member 2. The slide unit 53 includes a slide liner 54 that is slidably disposed along the vertical hole 9a ′ of the housing 9 ′, and a rotation transmission shaft 55 that is rotatably attached to the slide liner 54. The rotation transmission shaft 55 is rotatably inserted in a main driving bevel gear 56 that is rotatably held in a vertical hole 9a 'of the housing 9'.
[0027]
The main drive bevel gear 56 is rotatably held in the vertical hole 9a 'of the housing 9', and its tooth portion is always meshed with the driven bevel gear 14. Further, the lower inner peripheral surface of the main driving bevel gear 56 is formed into a tapered hole portion 56a that expands downward, and is configured to be fitted to a later-described tapered shaft portion 55c of the rotation transmission shaft 55 .
[0028]
Further, the rotation transmission shaft 55 is formed at its upper part in a rectangular column part 55a having a substantially quadrangular cross section, and this rectangular column part 55a is always slidably fitted into the rectangular hole 4d of the output shaft 4b for output. It is configured to be able to rotate integrally with the shaft 4b. Further, the lower portion of the rotation transmission shaft 55 is formed in a spline portion 55b in which a large number of spline grooves are formed, and the spline portion 55b is configured so as to be able to fit and fit into the spline drive hole 20a of the connecting shaft 20. . Further, a portion of the rotation transmission shaft 55 corresponding to the tapered hole portion 56a of the main driving bevel gear 56 is formed in the tapered shaft portion 55c, and this tapered shaft portion 55c is fitted to the tapered hole portion 56a. Due to the wedge effect, the rotation transmission shaft 55 and the main drive bevel gear 56 are configured to be coupled together so as to be always rotatable .
[0029]
Next, the operation of rearranging the sockets 22, 23, 24 in the automatic screw tightening machine 100 will be described. Since operations other than the operation of rearranging the sockets 22, 23, and 24 are the same as those of the automatic screw tightening machine 1, description thereof is omitted here.
[0030]
When rearranging the sockets 22, 23, 24, first, the AC servo motor 4a is driven in the state shown in FIGS. 4 and 5, and the output shaft 4b is rotated until the rotary encoder 4c counts a predetermined rotation angle. . As a result, the rotation transmission shaft 55 is rotated, and this rotation is transmitted to the main drive bevel gear 56 fixed to the rotation transmission shaft 55 by the wedge effect. As a result, the turret head 15 rotates via the driven bevel gear 14 and the driven gear shaft 13, and a desired socket is disposed on the extension of the axis of the driver tool 4 (here, an example in which the socket 23 is disposed will be described. ).
[0031]
When the socket 23 is disposed on the axial extension of the driver tool 4, the air cylinder 51 subsequently extends the rod 51a to lower the slide unit 53, thereby separating the tapered shaft portion 55c and the tapered hole portion 56a . Thereby, the rotation transmission shaft 55 becomes rotatable with respect to the main driving bevel gear 56. After the tapered shaft portion 55 c and the tapered hole portion 56 a are separated from each other, the spline portion 55 b of the rotation transmission shaft 55 is fitted into the spline drive hole 20 a of the connecting shaft 20. At this time, since it is necessary to match the phases of the spline portion 55b and the spline drive hole 20a, the rotation transmission shaft 55 can drive the AC servo motor 4a after the taper shaft portion 55c and the taper hole portion 56a are fixed. Receiving and descending while rotating.
[0032]
When the spline portion 55b of the rotation transmission shaft 55 is fitted into the spline drive hole 20a, the lower limit switch 51b of the air cylinder 51 is turned on, and the hexagon bolt is tightened in the same manner as the automatic screw tightening machine 1 in response thereto. Thereafter, when it is necessary to rearrange the socket again, the air cylinder 51 contracts the rod 51 a to raise the slide unit 53, and the tapered hole portion 55 c of the rotation transmission shaft 55 is formed on the tapered shaft portion 56 a of the main driving bevel gear 56. They are mated and joined together by a wedge effect.
[0033]
In the first and second embodiments described above, the screw tightening tools 16a, 16b, and 16c are connected to the coupling 17, the liner 18, the slide shaft 19, the connection shaft 20, the spring 21, and the slide shaft 19. Rotation is transmitted from the rotation transmission shaft when the spline portion 11b (or 55b) of the rotation transmission shaft 11 (or 55) is fitted in the spline drive hole 20a formed by the sockets 22, 23, and 24 and formed in the connecting shaft 20. However, the same effects can be obtained by holding the sockets 22, 23 and 24 directly on the turret head 15 and forming spline drive holes on the end surfaces thereof. The sockets 22, 23, and 24 can be replaced with driver bits such as known cross-recessed screw driver bits and hexagonal hole screw driver bits according to the type of screw to be tightened.
[0034]
【The invention's effect】
According to the automatic screw tightening machine of the present invention, it is possible to select a screw that matches the screw to be tightened from among a plurality of driver bits. It is no longer necessary to prepare an automatic screw tightening machine, and it is possible to solve the conventional problems in the case of configuring as an automatic unit using a robot or the case of configuring as a manual operation unit using a balancer unit or the like. . Further, the rotational drive of the turret head and the rotational drive of the driver bit can be performed by a single rotational drive source, and the apparatus can be configured to be extremely rational, lightweight and compact. In addition, since rotation is transmitted only to a necessary screw tightening tool among a plurality of screw tightening tools, there is an advantage that a load applied to the rotational drive source can be reduced.
[0035]
Further, as described in the second embodiment, when the rotation transmission shaft is coupled to the main driving bevel gear, the rotation of the output shaft is transmitted to the turret head, and the rotation transmission shaft is separated from the main driving bevel gear and connected to the screw tightening tool. By doing so, by configuring so that the rotation of the output shaft is transmitted to the screw tightening tool, it is possible to improve the operation characteristics by minimizing the movable parts. In addition, since the rotation transmission shaft and the main driving bevel gear are integrally coupled by the wedge effect due to the coupling between the tapered hole portion and the tapered shaft portion, they can be easily coupled and separated without phase matching. As a result, the drive control when switching the rotation transmission destination becomes extremely simple, and the device can be made more rational, lightweight and compact.
[Brief description of the drawings]
FIG. 1 is a front view showing a cross-section of a part of an automatic screw tightening machine according to a first embodiment of the present invention.
FIG. 2 is a side view in which a part of the automatic screw tightening machine according to the first embodiment of the present invention is cut out to have a cross section.
FIG. 3 is an operation explanatory view of the automatic screw tightening machine according to the first embodiment of the present invention.
FIG. 4 is a front view in which a part of an automatic screw tightening machine according to a second embodiment of the present invention is cut out and taken as a cross section.
FIG. 5 is a side view in which a part of an automatic screw tightening machine according to a second embodiment of the present invention is cut out to have a cross section.
FIG. 6 is an operation explanatory view of an automatic screw tightening machine according to a second embodiment of the present invention.
FIG. 7 is an explanatory view showing a state in which a conventional automatic screw tightening machine is attached to a balancer unit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Automatic screwing machine 4 Driver tool 4a AC servo motor 4b Output shaft 5 Rotation transmission switching mechanism 6 Air cylinder 8 Slide gear unit 11 Rotation transmission shaft 12 Drive bevel gear 14 Driven bevel gear 15 Turret heads 16a, 16b, 16c Screw tightening tool 22 , 23, 24 Socket 100 Automatic screwing machine 50 Rotation transmission mechanism 51 Air cylinder 55 Rotation transmission shaft 55c Taper shaft portion 56 Main drive bevel gear 56a Taper hole portion

Claims (1)

An output shaft that is rotatable by being driven by a rotational drive source; and
A rotation transmission shaft disposed so as to be capable of reciprocating while maintaining a rotatable state with the output shaft;
Operation means for operating the rotation transmission shaft to reciprocate;
A main driving bevel gear that is arranged so as to be coupled to and separated from the rotation transmission shaft along with the reciprocation of the rotation transmission shaft, and that can rotate integrally with the rotation transmission shaft when coupled.
A driven bevel gear that always meshes with the main drive bevel gear;
A turret head that can rotate integrally with the driven bevel gear;
A plurality of screw tightening tools arranged on the turret head and sequentially arranged at a predetermined position as the turret head rotates, and connected to the rotation transmission shaft separated from the main driving bevel gear at the predetermined position. equipped with a door,
A taper hole is formed in one of the main driving bevel gear and the rotation transmission shaft, and a taper shaft that can match the taper hole is formed on the other. The taper hole and the taper shaft are reciprocated by the rotation transmission shaft. An automatic screw tightening machine configured so that the main driving bevel gear and the rotation transmission shaft are coupled and separated without phase matching when the parts are matched and separated .

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