JP3575581B2 - Electric gun - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric pressurized resistance welding machine. It relates to a drive unit that can be replaced.
[0002]
[Prior art]
Conventionally, an electric motor that directly pressurizes the electrode tip of an electric gun can be changed to an arbitrary position on the circumference of the same axis as the ball screw to avoid interference with the jig. It has been proposed by the same applicant as the present application (JP-A-7-32159).
[0003]
In the device disclosed in Japanese Patent Laid-Open No. 7-32159, a drive shaft of an electrode passes through a bearing provided at a front portion of a main body casing, and a drive unit is mounted on a head portion of a casing that houses the penetrated drive shaft. In order to prevent the electric motor included in the drive unit from hitting a work or a jig, the rear cover can be replaced with another one to replace the electric motor.
[0004]
The present invention shows a more specific structure so that the electric motor can be easily rearranged in this kind of gun.
[0005]
[Problems to be solved by the invention]
As is well known, the operating conditions and the surrounding environment of a robot gun arranged on a spot welding line in an automobile assembly factory differ between the right line and the left line due to the positional relationship of a work, a jig, and other peripheral devices. For this reason, in the current automobile assembly line, a gun dedicated to either the RL or the RL is prepared in order to avoid interference between the gun and a jig.
[0006]
In the case of an electric gun as well, the mounting position of the electric motor built into the drive unit is fixed to either the left or right, so if the right line gun is used for the left line, the electric motor will interfere with the workpiece or jig Due to the problem, the conventional electric gun could not share the RL.
[0007]
Therefore, according to the device disclosed in Japanese Patent Application Laid-Open No. 7-32159, the arrangement of the electric motor can be changed by replacing the rear cover of the casing with a component, but the component replacement requires a reduced number of components and man-hours. It is not practical because it increases.
[0008]
In view of the above, the present invention enables the arrangement of the electric motor in one drive unit to be arbitrarily and easily rearranged in the direction of 360 ° around the drive shaft of the electrode chip without replacing extra parts as in the prior art. The aim was to overcome the problem of interference with the jig and expand the practical use of the RL shared type of the electric pressurized drive unit, and also to standardize the drive unit for the manufacturing side to improve productivity and reduce costs. I do.
[0009]
[Means for Solving the Problems]
The present invention has been developed to achieve the above object, and has the following technical means.
[0010]
That is, between the gun arm supported electrode tip in one of (2) (1) and supported by the driving device to the other of said gun arms (5) the other electrode tip performing pressurization to the opening movement by (3) An electric pressurized resistance welding machine for sandwiching a workpiece, generating a necessary pressing force between the electrode tips, applying a welding current and welding the same , wherein the driving device presses / releases the electrode tips. an electric motor (M) having as a driving source, the electrode drive shaft that operates the electrodes pressurized to open into a reciprocating linear motion by the rotation motion of the electric motor and a ball screw (16) a ball nut (17) (6) and a casing (7) for accommodating the drive shaft, said to constitute one of the drive unit by the power of the electric motor and a power transmission mechanism for transmitting the electrode driving shaft (8), included in the drive unit The electric motor is mounted on a common base (10), and the casing head (9) is provided with tapped holes at several angles on a circle concentric with the drive shaft center line XX. The common base is provided with cut holes having several angles corresponding to the tap holes, and the common base and the casing are detachably attached to the tap holes and the cut holes via fastening means. The arrangement of the electric motor can be changed by selectively rearranging the cut holes corresponding to the tapped holes from among the several angles .
[0011]
[Action]
The present invention realizes a common left and right electric gun because the electric motor can be freely rearranged in a 360-degree direction about the drive shaft. There is no need to prepare spare parts, and the use of the left and right electric guns dramatically improves the work efficiency of gun assembly and maintenance, contributing to a significant reduction in production costs.
[0012]
【Example】
Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a diagram showing the entire front view of a C gun for electric pressure spot welding and a cross section of a drive unit. FIG. 2 is a detailed sectional view of the drive unit. FIG. 3 is a view on arrow YY of FIG. 2 with the cover of the drive unit removed.
[0013]
The electrode tip 1 is supported on one side of a gun arm 2 made of a high-strength brass casting. The other electrode tip 3 is supported at the tip of an electrode drive shaft 6 which performs a pressing or opening motion by a driving device 5 supported on the other side of the gun arm via a support member 4. The C gun for spot welding generates a pressing force required for welding between two electrode tips by a driving device 5 to hold a workpiece, and a welding current flows between both electrodes to weld the workpiece.
[0014]
The driving device 5 includes an electric motor M provided as a driving source for pressurizing and releasing the electrode tip 2, and an electrode for converting the rotational motion of the electric motor into a reciprocating linear motion by a ball screw and a ball nut to perform the electrode pressing or releasing operation. A drive shaft 6, a casing 7 for accommodating the drive shaft, and a power transmission mechanism 8 for transmitting the power of the electric motor to an electrode drive shaft are provided. The common base is attached to the head portion 9 of the casing 7 so as to be detachable, thereby constituting one drive unit.
[0015]
The drive shaft 6 is housed in a casing 7 made of an aluminum alloy casting, and guides the electrode drive shaft 6 concentrically inside a front portion 11 of the casing 7 through which the electrode drive shaft 6 passes. The bearing 12 is stored. The tip of the electrode drive shaft 6 supports an electrode tip 3 which is directly pressurized for welding.
[0016]
The casing 7 and the support member 4 are detachably fixed with a plurality of bolts B1 via an insulating plate. The support member 4 is made of a high-strength brass casting that also serves as a front cover for fixing the bearing 12 of the front part.
[0017]
As the sliding bearing 12 provided at the front portion of the casing 7, a ball spline bearing which serves as a rotation stopper and a linear motion guide is used. The electrode drive shaft 6 is a ball spline shaft, and a ball nut 17 is fixed to an end. In the casing, a ball screw 16 penetrating a bearing 15 provided on the head portion 9 is incorporated in a ball nut 17 of the drive shaft 6. The electrode drive shaft 6 has a sliding bearing provided at the front portion of the casing as a ball spline bearing 12 and a linear motion guide and a rotation stopper are integrated into a unit, and the externally mounted rotation prevention mechanism is eliminated to eliminate electrode rotation. Consideration has been given to making the outer diameter of the casing 7 of the gun body including the shaft 6 thinner and lighter and smaller.
[0018]
The common base 10 is made of an aluminum alloy casting and is removably fastened to the head portion 9 of the casing 7 by a plurality of bolts B2. Holes are provided at four locations at a 90 ° pitch on a circle having the ball screw 16 on the same axis center line XX.
[0019]
The main body of the electric motor M is firmly fixed to the common base 10 by a plurality of bolts B3 (only six tap holes b3 corresponding to the bolts B3 are shown in FIG. 3). And a belt gear 18 fixed to the output shaft and a belt gear 19 fixed to the ball screw 16 are arranged in an enclosure space formed by the plate width (e) of the common base. .
[0020]
An aluminum alloy casting cover 21 is detachably fastened to the outside of the common base 10 by a plurality of bolts B4. The cover prevents foreign substances from entering the transmissions and ensures safety. Further, by removing this cover, it is possible to easily inspect the belt of the power transmission mechanism 8 housed inside the common base and replace parts of the transmission.
[0021]
In the power transmission mechanism 8, a timing belt 20 is stretched between a belt gear 18 and a belt gear 19 incorporated within a dimension (e) of the common base 10 in the plate width direction. The rotational force of the electric motor M rotates the ball screw 16 via the timing belt 20, and the rotational motion is converted into a linear motion by the ball nut 17, thereby causing the electrode drive shaft 6 to move directly.
[0022]
The same operation can be obtained by using a power transmission mechanism 8 in combination with a chain transmission type or gear transmission mechanism instead of the timing belt 20 of the present embodiment.
[0023]
The gun body is supported between the casing 7 and the gun bracket 22 for mounting the robot via an equalizing unit 23 as is well known in the art. A welding transformer 24 is supported on the gun bracket 22, and a conductive member constituting a secondary circuit is attached to an output terminal of the welding transformer by a shunt 26 and / or a bus bar 27 at the tip of the gun arm 2 and the electrode drive shaft 6. Connected to the tip holder 25.
[0024]
The case where the arrangement of the electric motor M in the above configuration is changed to the right or left side of the gun will be described. When the bolt B4 of the drive unit 5 is removed and the cover 21 is opened, the bolt B2 for fixing the common base 10 can be removed as it is, whereby the common base 10 can be removed from the head 9 of the casing 7 by 90 ° in four directions. That is, it can be rotated by 90 ° to each of the positions a, b, c, and d. By changing the direction of the common base 10 in this manner, the bolt B2 may be fixed at a position where the electric motor M can be avoided from the interfering object. That is, the common base 10 is removably attached to the head portion 9 of the casing 7 accommodating the drive shaft 6 from the plurality of bolts B2 as a fastening means, so that the common base 10 is disposed on a circle concentric with the shaft center line XX of the drive shaft. If the mounting angle (direction) of the common base is changed in accordance with the pitch of the plurality of bolt holes in the degree direction, the arrangement of the electric motor M can be freely changed from right to left or an intermediate position therebetween.
[0025]
In the embodiment of the present invention, as the fastening means of the common base 10, the cut holes and the tapped holes of the bolt B2 are provided at four positions at a 90 ° pitch in the circumferential direction around the drive shaft center. For fine division, it is easy to rearrange the bolt B2 at an arbitrary angle by narrowing the pitch of the tapped holes and the cut holes.
[0026]
【The invention's effect】
As described above, according to the device of the present invention, the common base on which the electric motor is mounted and the casing accommodating the electrode drive shaft are connected to the tap holes and cut holes formed at several angles through the fastening means. removably attaching, yet because alternatively the arrangement of the electric motor by recombining the cutting holes corresponding to said tapped holes from several angles are replaced by the previous SL drive shaft concentrically with Te, the same The motorized gun of the right and left can be used in common, eliminating the need to prepare a dedicated gun whose use is fixed as in the past and its spare parts. Standardization of the drive unit makes it possible to improve productivity and improve electric power. The work efficiency of gun assembly and maintenance of the type gun is dramatically improved, leading to cost reduction.
[Brief description of the drawings]
FIG. 1 is a sectional view of a C gun for electric pressurized spot welding showing an embodiment of the present invention.
FIG. 2 is a sectional view showing an embodiment of the drive unit of the present invention.
FIG. 3 is a view taken in the direction of arrows Y in FIG. 2;
[Explanation of symbols]
REFERENCE SIGNS LIST 1 electrode tip 2 gun arm 3 electrode tip 4 support member 5 drive unit (drive device)
6 Electrode drive shaft 7 Casing 8 Power transmission mechanism 9 Head 10 Common base 12 Bearing 16 Ball screw 17 Ball nut 18 Belt gear 19 Belt gear 20 Timing bolt 21 Cover 22 Gun bracket 23 Equalize unit 24 Welding transformer 25 Tip holder 26 Shunt 27 Busbar

Claims (1)

Gun arm workpiece between the other electrode tip to conduct pressurized to opening motion by supported electrode tip in one of (2) (1) and supported by the driving device to the other of said gun arms (5) (3) An electric pressure type resistance welding machine for generating a necessary pressing force between the electrode tips, applying a welding current and welding the electrode tips, wherein the driving device presses / releases the electrode tips. as the electric motor (M) with said electrode drive shaft that operates the electrodes pressurized to open and convert the linear reciprocating motion by the rotary motion of the electric motor and ball screw (16) a ball nut (17) (6) and the a casing (7) for housing the drive shaft, said to constitute one of the drive unit by the power of the electric motor and a power transmission mechanism for transmitting the electrode driving shaft (8), the collector included in the drive unit A motor is mounted on a common base (10), and a tap portion having several angles is provided on the head part (9) of the casing on a circle concentric with the drive shaft center line XX. Are provided with cutouts at several angles corresponding to the tapholes, and the common base and the casing are detachably attached to the tapholes and the cutouts via fastening means. An electric gun characterized in that the arrangement of the electric motor can be changed by selectively re-arranging a cutout corresponding to the angle from among the above-mentioned several angles.

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