JPH0295563A - Automatic grinding device for welding excess metal - Google Patents

Abstract

PURPOSE:To efficiently execute grinding with maintaining the specified balance by controlling the height for the base metal of an electronic grinder by the output of a sensor detecting the balance of immediately after grinding and providing a circuit for controlling a travelling truck so that the load current of the electronic grinder may maintain the specified reference current value on a grinding device. CONSTITUTION:A reference value corresponding to the specified balance value is set in advance, compared with the output from the potentiometers incorporated to the reference value and a sensor, a motor 9 for lift is rotated positively, stopped and reversely according to the size thereof and an electronic grinder 15 is lifted or stopped. Thus the grinding balance 52 of an excess metal 51 is held constant at all times for a base metal. As a result, the load current of the electronic grinder 15 fluctuates corresponding to the undulation of the excess metal 51 built up on the base metal, but by controlling a travel mechanism part 6 so as to become a fixed value by detecting this load current, the traveling truck 4 of the electronic grinder is adequately accelerated or decelerated according to the state of the undulation of the excess metal and the excess metal 51 is ground with good efficiency.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an automatic grinding device for welding excess metal.

[Prior art] Welding excess is often polished away for the purpose of improving the fatigue strength of welded joints, facilitating non-destructive testing of welded parts, or simply eliminating surface irregularities. It is being said. It is also common practice to grind the surface of a gas-cut weld groove, or to grind the surface of a cast or forged product.

The weld bead 51 is an extra weld bead 51 built up from the base metal surface 50 as shown in Fig. 10, and the conventional manual work is mechanized to remove it by grinding until it is almost flat with the base metal surface. In order to do this, an attempt was made to use a device as shown in FIG.

This device consists of a traveling carriage 60 that moves along the surface of the base material in the direction of the welding line. Lifting mechanism 61 installed on the traveling trolley
, a grinder 63 fixed to the elevating mechanism via a fixture 62, and a grindstone 64 attached to the grinder.The traveling carriage is driven by a motor, but the elevating mechanism is manually adjusted.

FIG. 7 shows an outline of the lifting mechanism, and the screw mechanism 66
The fixture 62 is attached to a block 67 that moves up and down, so when the knob 68 is turned left and right by hand, the grinder 63 moves up and down via the block 67 and the fixture 62, and as a result, the grinding wheel 64 moves up and down. The suspension for grinding the extra material 51 can be adjusted.

[Problems to be Solved by the Invention] As shown in FIGS. 11 and 12, grindstones in which a large number of polishing cloth pieces 64b are laminated radially on a circular substrate 64a made of aluminum alloy or the like are widely used. It is used.

Since the grinding surface of this seed grindstone 64 is renewed by the wear of the polishing cloth 64b during grinding, the amount of grinding removed per unit time is much greater than that of conventional offset grindstones, and the work efficiency is good. However, since the grinding wheel inevitably wears out quickly, in the apparatus shown in FIG. 8, the operator must always lower the grinder 63 to the base material surface 50 as the grinding wheel wears out.

In order to avoid this kind of trouble, it is possible to use a spring, pneumatic pressure, or hydraulic device to constantly press the grinding wheel against the backing at a constant pressure. In this case, it remains in the residual ff1h after grinding, so not only can the objective of achieving a flat finish along the surface of the base material not be achieved, but the grinding wheel also bites into the base material in areas 51a where the residual material is less hard. There is a risk of removing the polishing material.

The object of the present invention is to provide an automatic grinding device that eliminates the above-mentioned drawbacks.

[Means for Solving the Problems] In order to achieve the above object, the present invention automatically follows the wear of the grinding wheel even if the spacing is uneven, as long as there is no severe deformation on the surface of the base material. As shown in FIG. 14, the present invention provides a means for polishing so that the residual ah remains constant along the surface of the base material.

In other words, in a grinding device that removes excess welding material by grinding, there is an electronic grinder whose load current increases or decreases depending on the grinding depth per unit time, a traveling mechanism equipped with the electronic grinder, and a grinding device that removes residual material from welding immediately after grinding. The electronic grinder includes a sensor that detects the amount, a lifting mechanism that raises and lowers the electronic grinder, and a control unit. A traveling mechanism section ll that operates so that the load current of
It is characterized by comprising an llTm circuit and an overload prevention circuit that operates when the load current of the electronic grinder reaches a limit value.

[Function] A reference value corresponding to a predetermined remaining amount value is set in advance, and the reference value is compared with the output from the potentiometer built into the sensor, and the lifting mechanism is controlled according to the magnitude. Therefore, the lifting motor rotates forward, stops, and reverses according to the output of the potentiometer to raise, lower, or stop the electronic grinder, and as a result, the remaining amount of grinding remaining on the base metal is always maintained constant. .

As a result of maintaining the remaining amount constant as described above, the load current of the electronic grinder fluctuates in response to the ups and downs of the extra layer built up on the base material, but the running mechanism detects this load current and maintains it at a constant value. Mil the part! Therefore, the traveling cart of the electronic grinder is operated efficiently by increasing and decelerating appropriately according to the undulations of the backing.

Further, if the load current of the electronic grinder exceeds a limit value, an overload prevention circuit is activated to immediately stop the operation of the lifting motor, traveling motor, and grinder motor,
Prevent unexpected accidents in advance.

[Example] Hereinafter, the present invention will be specifically explained based on the drawings.

FIG. 1 is a front view schematically showing the present invention, and FIG. 2 is a side view.

As shown in the figure, the present invention includes a guide rail 1 and a traveling bogie 4.
, a traveling mechanism section 6 , a lifting mechanism 8 , a sensor 10 , and an electronic grinder 15 .

The guide rail 1 is provided on the side of the weld line in parallel with the weld line, and is placed on a support stand 2 equipped with a magnet (with a vacuum suction pad if the base material is a non-magnetic material). Are there guides on both sides of guide rail 1? 1lS12 is installed, and rack 3 is installed on the top surface.
This is provided. A binion 20 is made to protrude from the lower part of the traveling truck 4 and is engaged with the rack 3 provided on the guide rail,
The guide groove 12 is made to run through a plurality of guide wheels 11. The traveling mechanism section 6 has a built-in traveling servo motor 9, which rotates the pinion 20 via a deceleration mechanism. During the grinding work of the welding excess, the servo motor 9 for running is driven as described above to run at a relatively low speed, but after the grinding is completed, the handle 21 provided at the top of the running mechanism is operated to move the pinion. 20 is separated from the rack 3, and the traveling cart 4 can be quickly returned by hand.

The lifting mechanism 8 raises and lowers the electronic grinder 15 with respect to the base material surface 50. As schematically shown in FIG. Directly connected to slider 13
The support block 27 is screwed onto the support block 27.

Since the support block 27 is supported so as to be slidable in the vertical direction along left and right guides 28, the holder 16 attached to the slider 13 and the electronic grinder 15 are raised and lowered by rotating the motor 25.

The sensor 10 consists of a mounting bracket 30 that is detected on the weld line immediately after grinding from the frame of the lifting mechanism 8, a frame 31 that is pressed toward the base material surface by a spring 33 from the mounting bracket, and a frame 31 that is constantly pressed against the base material surface at the lower end of the frame. A wheel 37 that rotates in contact with the grinding surface, a rod 36 that is pressed from the frame toward the grinding surface by a spring 35, a wheel 32 that rotates while constantly contacting the grinding surface at the lower end of the rod, and an excess buildup after grinding ah It consists of a potentiometer 34 that detects.

That is, the potentiometer 34 is an element that electrically detects the height h of the remaining amount relative to the base material surface 50 when the wheel 32 comes into contact with the remaining amount surface immediately after grinding.

The mounting position of the mounting bracket 30 is such that the traveling trolley 4 can always maintain a predetermined height with respect to the base material while traveling, and the position of contact with the residual surface of the wheel 32 is such that it can be positioned at a position immediately after grinding. Any location may be used as long as it can ensure the shortest distance.

The control section includes a lifting mechanism control circuit (FIG. 4), a travel mechanism control circuit (FIG. 5), and an overload prevention circuit (FIG. 6).

The lifting mechanism control circuit is as shown in FIG.
a, a potentiometer 46a that outputs a comparison signal to the comparator, a remaining amount setter 42a that outputs a reference signal, a sensitivity adjustment circuit 43a, a forward/reverse stop switching circuit 44a, and a motor for lifting and lowering, such as a reversible motor 25. and has
The comparison signal is generated by electrically converting the remaining ff1h detected by the wheel 32 of the sensor 10 and sending it to the potentiometer 46.
The reference signal is a signal output from a, which corresponds to a predetermined reference signal output from the remaining amount setter 42 and serves as a reference for the υ control.

The sensitivity adjustment circuit 43a is, for example, a Schmitt circuit or the like.
The reason why the output signal changes to either positive or negative is to provide hysteresis to the input signal so that it does not operate against instantaneous input fluctuations. The forward/reverse stop switching circuit 44a uses, for example, a bridge driver circuit, and is configured to operate the motor 25 in four modes: forward, reverse, stop, and brake.

That is, the reference signal input to the comparator 41a is compared with the comparison signal, and the comparison output operates the forward/reverse stop switching circuit 44a to cause the lifting motor 25 to operate in four modes of forward/reverse stop braking. The residual AH is always maintained at a predetermined reference setting value by making the comparison output zero.

The traveling mechanism control circuit includes a comparator 41 as shown in FIG.
b, and the grinder motor 15a of the electronic grinder 15.
, a load current detection circuit 46b that detects the load current of the grinder motor and outputs a comparison signal to the comparator 41b via the rectifying and smoothing circuit 45, and the grinder motor 15.
A reference current setter 42b outputs a reference signal that corresponds to a predetermined reference current value of a and serves as a reference for control, and a speed setting signal outputted from a comparator 41b and the speed of a traveling motor such as a servo motor 9 are detected. A comparator 41c that pans the signal of the T G 46c and outputs a comparative output to the speed setting circuit 44b, the setting circuit 44b, and the servo motor 9.
It consists of a sensitivity adjustment circuit 43b. In order to keep the load current of the grinder motor 15a constant, the comparator 41b detects the load current of the motor 15a using the load current detection circuit 46b, compares the detected output with a reference value, and adjusts the servo motor 9 appropriately. It is designed to output a speed setting circuit to control the speed.

Further, the comparator 41c detects and feeds back the speed of the motor 9 with respect to the speed setting value using the TG 46c, and controls the speed of the motor 9 accurately in response to the speed setting signal from the comparator 41b. be.

Further, the sensitivity adjustment circuit 43b includes the sensitivity adjustment circuit 43a.
It has the same function as .

As shown in FIG. 6, the overload prevention circuit includes an overload reference current setting device 42c, a comparator 41d, and an overload prevention circuit 44.
The load current detection signal detected by the load current detection circuit 46b and inputted to the comparator 41d via the rectification and smoothing circuit 45 is transmitted to the overload reference setting circuit 42c. When the predetermined limit value is exceeded, the output of the comparator 41d operates the power supply opening device 49 via the overload prevention circuit 44c, and stops the lifting motor 25, the grinder motor 15a, and the traveling motor 9. This is how it was done.

The specific operation of the above-mentioned overload prevention circuit is that when the detected load current value exceeds a predetermined limit value, first, the lifting motor 25 is raised, and at the same time the traveling motor 9 and the grinder motor 15a are turned on. It is preferable to stop the lifting motor 25 with an appropriate time rack.

In use, since the sensor 10 outputs a comparison signal indicating the remaining amount of excess material immediately after grinding, the comparator 41a compares this signal with a reference signal corresponding to the remaining amount preset by the remaining amount setting device 42a. After comparison, if the actual remaining amount is larger than the set value, the lift motor 25 is operated to lower the grinder toward the surface of the base material, and conversely, if the actual remaining amount is smaller than the set value, the lift motor 25 is moved up. drive. Therefore, if there is no deformation at all on the surface of the base material, the grinder is always lowered by the amount of wear of the grindstone, and the extra heel is maintained at the set value. If the surface of the base material is deformed, the grinder is moved up and down or stopped to simultaneously follow the wear of the grindstone and the deformation of the surface of the base material. 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 made as small as practicable, not only the amount of wear of the grinding wheel during that period but also the normal Tracking errors due to deformation of the material surface can also be ignored in practice. (For example, if the distance between the grinding point and the sensor is deviated by 20tm, the tracking error will be 0.06 even if the deformation gradient of the base material surface in the weld line direction is at most 3/1000.
It's just ttm. ) On the other hand, the grinder motor 15a of the electronic grinder is
When the amount of grinding removed per medium time increases and the rotational speed is about to drop, the load current is increased to maintain the rotational speed constant, so if the cross-sectional area of the extra material to be removed by grinding is constant, There is a relationship as shown in FIG. 7 between the moving speed of the traveling truck and the load current of the electronic grinder. Utilizing such characteristics of the electronic grinder, the traveling mechanism section 1 of the control section.
The II control circuit controls the moving speed of the traveling trolley. That is, the load current of the grinder motor 15a is detected by the detection circuit 4.
6b, the rectifying and smoothing circuit 45 converts the noise into direct current, and then removes noise. This output signal is compared with a predetermined reference value set by a preset reference current setting device 42b by a comparator 41b, and when the load 1 current is smaller than the reference value, the moving speed of the truck is increased; Sensitivity adjustment circuit 43b, comparator 41C1 and speed setting circuit 44 reduce the moving speed of the cart when the load current is larger than the set reference value.
The speed of the traveling motor 9 is controlled by the closed circuit consisting of the drive motor 9 and the drive motor 9. With this kind of control, even if there is considerable variation in the amount of excess material to be removed by grinding (which tends to occur at welding bead joints, etc.),
In response to this, the grinding work can be automatically performed at a speed that is reasonable and efficient.

Sensitivity adjustment circuits 43a and 43 in FIGS. 4 and 5
b is a circuit that adjusts the width of the dead zone in order to prevent hunting of the lifting motor 25 and the running motor 9, respectively, as described above.

The overload prevention circuit is a protection circuit that stops all operations when the load current of the grinder motor 15a reaches the allowable limit value shown in FIG. 7, and prevents burnout of the grinder and damage to the grindstone. can do. Also, the 11th
~ When using the grindstone shown in Figure 12, if the wear of the polishing cloth reaches the circular substrate and grinding is no longer possible, the grinding resistance will inevitably increase and the grinder load current will exceed the allowable limit, so overload can be prevented. A circuit is activated and the operation of the device is automatically stopped, allowing the grindstone to be replaced. According to experimental results, the circuit shown in Figure 4, which uses an AC reversible motor as the lifting motor, can provide a sufficiently smooth finished surface.
Using a servo motor further improves control accuracy.
A smoother finished surface can be obtained.

[Effects of the Invention] The present invention provides a residual grinding device equipped with an electronic grinder that increases or decreases the load current according to the grinding speed, and is equipped with a sensor that detects the remaining amount immediately after grinding, and uses the output of the hinger to control the electronic grinder. A lifting l1lWU control circuit that controls the height of the electronic grinder with respect to the base material and a traveling mechanism control circuit that controls the traveling carriage to maintain the load current of the electronic grinder at a predetermined reference current value are provided. It is possible to automatically maintain a predetermined residual h1 regardless of the situation, and to control the traveling speed according to the ups and downs of the overfill for efficient grinding.In addition, an overload prevention circuit is installed to prevent abnormal situations. We can provide a grinding device that can handle this.

[Brief explanation of drawings]

Fig. 1 is a front view of the grinding device of the present invention, Fig. 2 is a side view, Fig. 3 is a schematic front view of the elevating mechanism, Fig. 4 is a block diagram of the elevating mechanism 1ilI111 circuit, and Fig. 5 is the traveling mechanism section. A block diagram of the control circuit, Fig. 6 is a block diagram of the overload prevention circuit, Fig. 7 is a characteristic diagram of the electronic grinder, Fig. 8 is a front view of the conventional grinding device, and Fig. 9 is the lifting mechanism in the same device. 10 is an enlarged sectional view of the welding reinforcement,
Figures 11 and 12 are a front view and a cross-sectional view of the grindstone;
FIGS. 13 and 14 are longitudinal cross-sectional views of the weld reinforcement. DESCRIPTION OF SYMBOLS 1... Guide rail, 2... Support plate, 3... Rack, 4... Traveling trolley, 6... Traveling mechanism section, 8...
Lifting mechanism, 9... Traveling motor, 10... Sensor,
DESCRIPTION OF SYMBOLS 11... Guide wheel for traveling, 12... Guide groove, 13... Elevating slider, 15... Electronic grinder, 17... Grinding wheel desk, 20... Binion, 2
1... 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, 41a
, 41b, 41c. 41d...Comparator, 42a...Remaining amount setting device, 42b
... Reference current setter, 42c... Reference current setter for overload, 43a, 43b... Sensitivity adjustment circuit, 44a.
...Forward/reverse stop switching circuit, 44b...Speed setting circuit, 4
4c... Overload prevention circuit, 45... Rectifier smoothing circuit,
46a...Potentiometer, 46b...Load current detection circuit, 46c...TG, 49...Power supply ■1 device, 50...Base metal surface, 51...Extra layer, 52... Remaining ω. Figure 4

Claims (1)

[Claims] 1. In a grinding device that removes excess welding, etc.
An electronic grinder whose load current increases or decreases depending on the amount of grinding per unit time, a traveling mechanism section equipped with the electronic grinder, a sensor that detects the amount of excess material remaining immediately after grinding, and an elevating mechanism that raises and lowers the electronic grinder. , a control section, the control section includes a lifting mechanism control circuit that operates so that the remaining amount is constant based on the sensor output, and a traveling mechanism control circuit that operates so that the load current of the electronic grinder is constant. 1. An automatic grinding device for welding overfill, comprising: a circuit; and an overload prevention circuit that operates when the load current of an electronic grinder reaches a limit value.