JPH07115286B2 - Automatic welding equipment for welding excess - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an automatic grinding apparatus for removing welding excess by using a constant speed rotary electric grinder whose load current increases and decreases according to the grinding amount per unit time. .

[Prior Art] It is possible to grind away excess welds for the purpose of improving the fatigue strength of welded joints, facilitating nondestructive testing of welds, or simply eliminating surface irregularities. It is being appreciated. Further, it is common practice to finish the gas-cut welding groove surface by grinding, or the casting and the surface of the casting.

As shown in Fig. 10, the weld surplus refers to the weld bead 51 that is overlaid from the base metal surface 50.Mechanization of conventional manual work is performed in the work of grinding and removing this until it becomes almost flat with the base metal surface. Attempts have been made to use a device such as that of FIG.

This device includes a traveling carriage 60 that moves in the welding line direction along the surface of the base material, an elevating mechanism 61 mounted on the traveling carriage, and a grinder 63 fixed to the elevating mechanism via a fixture 62.
It consists of a grinding wheel 64 mounted on the grinder, and the traveling carriage is driven by a motor, but the lifting mechanism is manually adjusted. FIG. 9 shows an outline of an elevating mechanism. Since the fixing tool 62 is attached to a block 67 that moves up and down by a screw mechanism 66, when the knob 68 is turned left and right by hand, the block 67 and the fixing tool are moved. The grinder 63 moves up and down via 62, and as a result, the amount by which the grinding wheel 64 grinds the extra deposit 51 can be adjusted.

[Problems to be Solved by the Invention] As a grindstone used here, as shown in FIGS. 11 to 12, a large number of polishing cloth pieces 6 are formed on a circular substrate 64a made of an aluminum alloy or the like.
A radial stack of 4b is widely used.

The ground surface of the seed grindstone 64 is renewed due to the wear of the polishing cloth 64b accompanying grinding, so that the amount of grinding removed per unit time is remarkably larger than that of the conventional offset grindstone and the work efficiency is good. However, since the wear of the grindstone is inevitably high, the operator of the apparatus shown in FIG.
The grinder 63 must be lowered onto the base metal surface 50.

In order to save such trouble, it is conceivable to use a spring, air pressure, or a hydraulic device to constantly press the grindstone to a constant pressure, but as shown in Fig. 13, it was applied to the base metal surface. If the weld surplus is uneven and the amount of surplus is uneven, the remaining amount h remains even after grinding, so the goal of finishing the surface flat along the base metal surface cannot be achieved. There is a risk that the grindstone will bite into the base material and grind and remove it at the place 51a where the amount is small. In addition, the weld surplus may have local protrusions at the seams of the weld beads, etc., unlike the oxide scale of the steel sheet, and during grinding, the grinding wheel rotating at high speed collides with the protrusions. When it is damaged, fragments are scattered and it is very dangerous.

The present invention, as long as there is no significant deformation on the surface of the base metal, even if there are undulations in the weld surplus on the base metal, it is possible to perform grinding so that the surplus residual amount becomes constant by following the wear of the grinding wheel. With the aim of providing a grinding device, when the load current of the grinder reaches the limit value, the grinding wheel is retracted and raised,
It is an object of the present invention to provide an automatic grinding device capable of safely operating by stopping rotation of a grinder and traveling of a traveling carriage.

[Means for Solving the Problems] In order to achieve the above object, the present invention electronically controls so that the rotation speed hardly changes even if the rotation resistance changes, so that the motor current increases as the rotation resistance increases. An automatic grinding device for removing welding excess by using a grinder having a characteristic of continuously increasing monotonically, that is, a constant speed electric rotating grinder in which a load current increases and decreases according to an amount of grinding per unit time. .

This automatic grinding machine is equipped with a constant speed rotary electric grinder and a traveling carriage equipped with a traveling mechanism section, a constant velocity rotary electric grinder lifting mechanism section and a control section, and a position for hitting behind the grinding wheel in the traveling direction. And a sensor for detecting the height of the welding surplus remaining amount attached to the traveling carriage; the control unit compares the sensor output with the welding surplus remaining amount set value, and the remaining amount becomes constant. As such, a lifting mechanism control circuit that raises and lowers the constant-speed rotary electric grinder, and a traveling mechanism control circuit that detects the load current of the electric grinder and drives the traveling carriage by adjusting the traveling speed so as to match the current setting value, When the load current of the electric grinder reaches the limit value,
Drive the lifting mechanism to the ascending side to raise the grinding wheel,
And an overload prevention circuit for stopping the rotation of the electric grinder and stopping the traveling of the traveling carriage.

[Operation] Set the standard corresponding to the predetermined surplus remaining amount value in advance,
The reference value and the output from the potentiometer built into the sensor are compared, and the lifting mechanism is controlled according to the size of the sensor. Therefore, the lifting motor is normally rotated or stopped according to the output of the potentiometer. Reverse rotation causes the constant-speed rotary electric grinder to move up and down or stop, and as a result, the surplus remaining amount after grinding is always kept constant with respect to the base material.

As a result of keeping the remaining amount constant in this way, the load current of the electric grinder fluctuates corresponding to the undulations of the extraneous material on the base metal (see Fig. 14). Since the traveling mechanism is controlled so that the traveling mechanism of the electric grinder is accelerated and decelerated appropriately according to the condition of the undulations of the extra-height, the vehicle can be efficiently operated.

Further, when the load current of the constant speed rotary electric grinder exceeds the limit value, the overload prevention circuit is activated to appropriately stop the operation of the lifting motor, the traveling motor, and the grinder motor to prevent an unexpected accident. Prevent in advance.

In the present invention, there is no problem even if a normal offset grindstone is used, but in order to avoid a decrease in the grinding ability due to clogging, when using a grinding cloth laminated grinding wheel shown in FIGS. 11 to 12, particularly effective Is remarkable.

EXAMPLES The present invention will be specifically described below with reference to the drawings. FIG. 1 is a front view showing the outline of the grinding apparatus of the present invention, and FIG. 2 is a side view of the same.

The main part of the device of the present invention is, as shown in the figure, a guide rail 1, a traveling carriage 4, a traveling mechanism section 6, and a lifting mechanism 8
, A sensor 10, and a constant speed rotary electric grinder 15 having a grinding wheel 17. An offset grindstone or a polishing cloth laminated grindstone is used as the grinding grindstone 17.

The guide rail 1 is placed on an upper part of a support base 2 with a magnet provided on the side of the welding line and in parallel with the welding line. When the base material is a non-magnetic material, the support base 2 with a vacuum suction pad is used. Guide grooves 12 are provided on both sides of the guide rail 1,
A rack 3 is provided on the upper surface. The pinion 20 is projected below the traveling carriage 4 to be engaged with the rack 3 provided on the guide rail, and a plurality of guide wheels 11 are vertically provided at left and right positions sandwiching the pinion 20 to guide the guide groove 12. Engage with.

A traveling motor (for example, a servomotor) 9 is built in the traveling mechanism section 6 and rotates the pinion 20 via a speed reducing mechanism (not shown). At the time of grinding the excess weld, the traveling motor 9 is driven to drive at a relatively low speed.
After finishing the grinding, the handle provided on the upper part of the traveling mechanism section 6
The pinion 20 is separated from the rack 3 by operating 21 and the traveling carriage 4 can be quickly returned by pushing manually.

The lifting mechanism 8 uses the low-speed rotating electric grinder 15 on the surface 50 of the base material.
As shown in FIG. 3, the reversible motor 25 is placed on the upper part of the elevating mechanism 8, and the screw rod 26 is directly connected to the motor output shaft and screwed to the support block 27 of the slider 13. Let Since the support block 27 is slidably supported in the vertical direction along the left and right guides 28, the slider 13 can be rotated by rotating the lifting motor 25.
Holder 16 and constant speed rotary electric grinder mounted on
Raise and lower 15.

The sensor 10 includes a mounting bracket 30 which is projected from the outer frame portion of the lifting mechanism 8 onto the welding line immediately after grinding, and a spring 33 from the mounting bracket 30.
Frame pressed downward (toward the surface of the base metal)
31, a wheel 37 attached to the lower end of the frame 31 to rotate in contact with the base material surface 50, a rod 36 pressed from the frame 31 toward the grinding surface by a spring 35, and attached to the lower end of the rod 36. It comprises a wheel 32 that constantly rotates in contact with the grinding surface, and a potentiometer 34 that electrically detects the surplus remaining amount h (FIG. 14) after grinding. The potentiometer 34 is an element for electrically detecting the height h of the remaining amount with respect to the base material surface 50 when the wheel 32 contacts the remaining amount surface immediately after grinding.

The mounting position of the mounting bracket 30 can always maintain a predetermined height with respect to the base material surface 50 while the traveling carriage 4 is traveling, and the contact position of the wheel 32 with the remaining surface is immediately after grinding. Any portion of the outer frame portion of the elevating mechanism 8 may be used as long as the shortest distance can be secured.

The control unit includes an elevating mechanism control circuit (FIG. 4) for elevating and lowering the electric grinder, a traveling mechanism control circuit (FIG. 5) for traveling the traveling carriage, and an overload preventing means (FIG. 6). There is.

The elevating mechanism control circuit includes a comparator 41a, a potentiometer 46a that outputs a comparison signal to the comparator 41a, a remaining amount setting device 42a that outputs a reference signal, a sensitivity adjusting circuit 43a, and a forward / reverse stop switching circuit 44a. And a lifting motor, for example, a reversible motor 25. The comparison signal is a signal output from the potentiometer 46a by electrically exchanging the remaining amount h detected by the wheel 32 of the sensor 10, and the reference signal is a predetermined reference remaining amount output from the remaining amount setting device 42a. Is a reference signal for control corresponding to.

The sensitivity adjusting circuit 43a is composed of, for example, a Schmitt circuit or the like, and when the output signal changes to either positive or negative, a hysteresis is provided to the input signal so that it does not operate in response to a momentary fluctuation of the input. Forward / reverse stop switching circuit 44a
Uses a bridge driver circuit to drive the lifting motor 25 in four modes: forward rotation, reverse rotation, stop, and brake.

That is, the reference signal input to the comparator 41a is compared with the output signal of the potentiometer 46a, the forward / reverse stop switching circuit 44a is operated by the comparison output, and the forward / reverse rotation of the lifting motor 25 is performed. The four modes of operation of the brake are operated so that the comparison output becomes zero, and the remaining amount h is always held at a predetermined reference set value.

As shown in FIG. 5, the traveling mechanism control circuit 40b controls the comparator 4
1b, a grinder motor 15a of the electric grinder 15, and
The comparator 41 detects the load current of the grinder motor.
A load current detection circuit 46b that outputs a comparison signal to the b through the rectifying / smoothing circuit 45, and a reference current setter 42b that outputs a reference signal serving as a control reference corresponding to a predetermined reference current value of the grinder motor 15a. , Speed setting circuit 44b, and comparator 41b
A tacho generator (T that detects the speed setting signal output from the motor and the speed of the traveling motor (eg, servo motor) 9
G) 46c signal is input and comparison output is set to speed setting circuit 44b
And a sensitivity adjusting circuit 43b.

The comparator 41b keeps the load current of the grinder motor 15a constant at all times.
The load current of 5a is detected, the output is compared with a reference value, and the traveling motor 9 is controlled to an appropriate speed. The speed of the traveling motor 9 is detected by the tacho generator (TG) 46c and fed back to the speed setting circuit 44b via the comparator 41c, and the speed of the traveling motor 9 is accurately controlled in accordance with the speed setting signal. The sensitivity adjustment circuit 43
b has the same function as the sensitivity adjustment circuit 43a.

As described above, the weld surplus may have local protrusions at the seams of the weld beads, etc., unlike the oxide scale of the steel plate, and during grinding traveling, the grindstone rotating at high speed collides with the protrusions. In the unlikely event that it breaks, the fragments will fly and it is extremely dangerous. Therefore, in the present invention, an overload prevention unit that outputs an operation signal when the load current of the constant speed rotary electric grinder reaches the limit value due to the occurrence of the abnormal situation as described above is provided,
It stops the rotation of the grindstone, raises and retracts it, and stops the running momentarily.

As shown in FIG. 6, the overload preventing means includes an overload reference current setting device 42c, a comparator 41d, an overload preventing circuit 44c,
It consists of a power switch 49. The load current detection circuit 46b
The load current detection signal detected by (FIG. 5) and input to the comparator 41d (FIG. 6) via the rectifying and smoothing circuit 45 is
When it exceeds the predetermined limit value of the overload reference current setting device 42c, the output of the comparator 41d operates the power switch 49 via the overload prevention circuit 44c, the lifting motor 25, the grinder motor 15a, The traveling motor 9 is stopped.

As a specific operation of the overload preventing means, when the load current detection value exceeds a predetermined limit value, first, the elevating motor 25 is driven to raise the electric grinder to a predetermined height at the same time. After stopping the traveling motor 9 and the grinder motor 15a, it is preferable to stop the lifting motor 25 with an appropriate time lag.

When using, the sensor 10 shows the remaining amount of excess just after grinding.
Since the comparison signal indicating 52 is output, the signal is compared with the reference signal corresponding to the remaining amount 52 preset by the remaining amount setting device 42 in the comparator 41a, and the actual remaining amount If it is larger, the grinder is lowered toward the surface of the base material, and conversely, if the actual remaining amount is smaller than the set value, the lifting motor is driven so as to be raised.
Therefore, if there is no deformation on the surface of the base material, the grinder always descends by the amount of wear of the grindstone and the surplus remaining amount is maintained at the set value.

If the base material surface 50 is deformed, the grinder is moved up and down or stopped simultaneously with the consumption of the grindstone and the deformation of the base material surface. In this case, the feedback control is delayed by the distance between the grinding point and the remaining amount detection point, but if this distance is as small as practical, not only the consumption of the grindstone during that time but also the mother wheel normally seen can be observed. Material surface
The tracking error due to the deformation of 50 can be practically ignored. (For example, if the distance between the grinding point and the sensor is 20 mm, the maximum deformation gradient of the base metal surface in the welding line direction is 3/10.
Even with 00, the tracking error is only 0.06 mm. ) On the other hand, grinder motor of constant speed rotary electric grinder 15
When the grinding removal amount per unit time increases and the rotation speed decreases, 15a controls so as to increase the load current and keep the rotation speed constant. For example, there is a relationship as shown in FIG. 7 between the traveling speed of the traveling carriage and the load current of the constant speed rotary electric grinder.

Utilizing such characteristics of the constant speed rotary electric grinder 15, the traveling mechanism control circuit of the control unit controls the traveling speed of the traveling carriage. That is, the load current of the constant speed rotary electric grinder is detected by the detection circuit 46b, and the rectifying / smoothing circuit 45 replaces it with direct current and then removes noise. This output signal is compared with a predetermined reference value preset by the reference current setting unit 42b by the comparator 41b. When the load current is smaller than the set reference value, the traveling speed of the traveling vehicle 4 is increased, and vice versa. When the load current is larger than the set reference value, the traveling motor 9 is driven by a closed circut composed of a sensitivity adjusting circuit 43b, a comparator 41c, a speed setting circuit 44b and a tacho generator 46c so as to reduce the moving speed of the traveling vehicle 4. Control the speed of.

By such control, even if there is a considerable variation in the amount of extraneous material to be removed by grinding (it is likely to occur due to the seam of welding beats, etc.), it is automatically adjusted at a reasonable speed without waste. Can be ground.

The sensitivity adjustment circuits 43a and 43b in FIGS. 4 and 5 are
This circuit adjusts the dead zone width to prevent hunting of the lifting motor 25 and the traveling motor 9.

The overload prevention circuit 44c is a protection circuit for stopping all operations when the load current of the grinder motor 15a reaches the allowable limit value of FIG. 7, and prevents burnout of the grinder and damage of the grindstone. Can be prevented.

Further, in the present invention, there is no problem even using a normal offset grindstone, in order to avoid a decrease in the grinding ability due to clogging, in the case of using a polishing cloth laminate type grindstone as shown in FIG. When the abrasion of the polishing cloth reaches the circular substrate and it becomes impossible to grind, the grinding resistance inevitably increases and the grinder load current exceeds the allowable limit value, so the overload prevention circuit 44c operates and the equipment operates. Will stop automatically and will be in a state of waiting for the replacement of the whetstone. According to the experimental results, a finished surface with sufficient smoothness can be obtained even with the circuit of FIG. 4 using an AC reversible motor as the lifting motor 25, but if a servo motor is used, the control accuracy is further improved and A smooth finished surface can be obtained.

[Advantages of the Invention] The present invention provides a surplus grinding apparatus equipped with a constant-speed rotary electric grinder that increases and decreases the load current according to the grinding amount, and is provided with a sensor for detecting the remaining amount immediately after grinding. Since an elevating mechanism control circuit for controlling the height of the electric grinder with respect to the base material and a traveling mechanism control circuit for controlling the traveling carriage to maintain the load current of the electric grinder at a predetermined reference current value are provided, The predetermined remaining amount can always be automatically maintained regardless of the ups and downs, and the traveling speed can be controlled according to the ups and downs of the extra ups, so that efficient grinding can be performed.

Also, when the load current of the electric grinder reaches the limit value due to an abnormal situation such as the grinding stone colliding with a local protrusion at the seam of the welding bead, etc., the grinding wheel is retracted and raised by the operation of the overload prevention circuit, You can work safely by stopping the rotation of the grinder and the traveling carriage.

[Brief description of drawings]

FIG. 1 is a front view of the grinding apparatus of the present invention, FIG. 2 is a side view of the same, FIG. 3 is a schematic front view of a lifting mechanism, FIG. 4 is a block diagram of a lifting mechanism control circuit, and FIG. FIG. 6 is a block diagram of a control circuit, FIG. 6 is a block diagram of overload prevention means, FIG. 7 is a characteristic diagram of a constant speed rotary electric grinder, FIG. 8 is a front view of a conventional grinding machine, and FIG. Fig. 11 is a schematic front view of the lifting mechanism in Fig. 10, Fig. 10 is an enlarged cross-sectional view of the weld surplus, and Fig. 11
FIG. 12 and FIG. 12 are a front view and a sectional view of the grindstone, and FIGS. 13 and 14 are a sectional view in the longitudinal direction of the weld overlay. 1 ... Guide rail, 2 ... Support plate, 3 ... Rack, 4
...... Trucking vehicle, 6 …… Traffic mechanism part, 8 …… Lift mechanism, 9
...... Running motor, 10 …… Sensor, 11 …… Running guide wheel, 12 …… Guide groove, 13 …… Up and down slider,
15 …… Constant speed rotary electric grinder, 17 …… Grinding wheel, 20…
… Pinion, 21 …… Handle, 25 …… Lifting motor, 26
...... Screw rod, 27 …… Support block, 28 …… Guide, 30 …… Mounting bracket, 31 …… Frame, 32 …… Sensing wheel, 33,35 …… Spring, 34 …… Potentiometer, 40a …… Lifting mechanism control circuit, 40b ... Traveling mechanism control circuit, 41a, 41b, 41c, 41d ... Comparator, 42a
…… Remaining amount setter, 42b …… Reference current setter, 43a, 43b…
… Sensitivity adjustment circuit, 44a …… Forward / reverse stop switching circuit, 44b …… Speed setting circuit, 44c …… Overload prevention circuit, 45 …… Rectification smoothing circuit, 46a …… Potentiometer, 46b …… Load current detection circuit, 46c ...... Tacho generator, 47 …… reference current setting device, 48 …… accelerating / decelerating circuit, 49 …… power switch, 50 …… base material surface, 51 …… extra, 52 …… remaining quantity.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chen Meitoku 5-3-20 Kitashinagawa, Shinagawa-ku, Tokyo Inside Akira Engineering Co., Ltd. (72) Takaaki Ishibashi 5-3 Kitashinagawa, Shinagawa-ku, Tokyo No. 20 in Akira Engineering Co., Ltd. (56) References JP-A-52-74548 (JP, A) JP-A-60-263613 (JP, A)

Claims (1)

[Claims] 1. A grinding device for grinding and removing welding surplus by using a constant speed rotary electric grinder whose load current increases and decreases according to the amount of grinding per unit time, and which is equipped with a constant speed rotary electric grinder. It is mounted on a traveling carriage equipped with a traveling mechanism, a constant-speed rotating electric grinder lifting mechanism, and a controller, and a traveling carriage located at the position behind the grinding wheel in the traveling direction to detect the amount of excess welding residue. The control unit compares the sensor output with a welding surplus remaining amount set value and raises and lowers the electric grinder so that the remaining amount is constant, and the electric motor. A traveling mechanism control circuit that detects the load current of the grinder and adjusts the traveling speed to drive the traveling carriage to match the current setting value, and when the load current of the electric grinder reaches a limit value,
Drive the lifting mechanism to the ascending side to raise the grinding wheel,
An automatic grinding machine for welding excess, which comprises an overload prevention circuit for stopping the rotation of the electric grinder and stopping the traveling of the traveling carriage.