JPH1058436A - Automatic feed concrete core drill - Google Patents

Abstract

(57) [Problem] The present invention relates to a control device for a concrete core drill, and prevents a feed speed during drilling from being unnecessarily increased even in a small-diameter core bit, so that cutting water is not clogged and stable. It is an object of the present invention to provide a control device for a concrete core drill capable of performing drilling. A feed speed during drilling is calculated by measuring the number of rotations of a feed motor, and an upper limit is set for the feed speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic feed concrete core drill.

[0002]

2. Description of the Related Art In a conventional automatic feed concrete core drill, since the load torque at the time of drilling is proportional to the current of the main motor, the current of the main motor is set to a predetermined value so that the load torque during drilling becomes constant. The feed rate of the electric drill was being adjusted.

[0003]

Since the feed speed of the electric drill is adjusted so that the current of the main motor becomes constant at a predetermined value, the feed speed becomes too fast with a small-diameter core bit, and the discharge of cutting powder cannot be made in time. There is a problem that cutting water is clogged and drilling cannot be performed.

An object of the present invention is to solve the above-mentioned problems and to provide a control device for a concrete core drill capable of stably piercing a cutting bit without cutting water being clogged even with a small-diameter core bit.

[0005]

The above object is achieved by providing means for detecting the number of revolutions of the feed motor and providing an upper limit to the number of revolutions of the feed motor during drilling.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. 1 is a base, 2 is an anchor bolt, 3
Is a drill stand, 4 is a main motor, 5 is an electric drill, 6
Is a feed motor, 7 is a control box, 8 is a core bit, 9
Is an AC power supply, 10 is a power switch, 13 and 15 are semiconductor control elements, 16 and 17 are ignition circuits, 18 is a current detection circuit, 20 is a power supply circuit, 21 is a microcomputer,
Reference numerals 22 and 23 denote drivers, and reference numeral 24 denotes a rotation speed detection circuit.
FIG. 2 is a flowchart showing the control procedure of the present invention in FIG. Hereinafter, the operation of the circuit shown in FIG. 1 will be described according to the procedure of FIG.

The start in FIG. 2 corresponds to a procedure in which the base 1 is fixed to concrete by the anchor bolt 2, the core bit 8 is fixed to the electric drill 5, and the power switch 10 is turned on. When the power switch 10 is turned on, the power circuit 20 operates, and the microcomputer 21 starts operating.

In step 201, when the microcomputer 21 starts operating, the microcomputer 21 transmits a drive signal of the main motor 4 to the semiconductor control element 13 in the order of the output port 215, the driver 22, and the ignition circuit 17 to rotate the main motor 4.

In step 202, the no-load current Io of the main motor 4 is detected via the current detection circuit 18 and stored in the microcomputer 21.

In step 203, the electric drill 5 is controlled at a constant speed (in this embodiment, 20 mm /
Minutes). In this operation, a drive signal is transmitted to the semiconductor control element 15 from the output port 217 in the microcomputer 21 to the driver 23 and the ignition circuit 16 in this order, and the feed motor 6 is driven.

In step 204, the current of the main motor 4 is detected via the current detection circuit 18, and the current of the main motor 4 is set to a predetermined value (in this embodiment, the previously detected no-load current Io
If + 2A) or more, it is determined that the core bit 8 has come into contact with the object to be drilled and has started drilling.

In step 205, the feed speed of the electric drill 5 is controlled so as to perform the drilling so that the current of the main motor 4 becomes a constant value Iref. That is, when the current of the main motor 4 is smaller than the target value Iref, the rotation speed of the feed motor 6 is increased, and when the current of the main motor 4 is larger than the target value Iref, the rotation speed of the feed motor 6 is decreased. The rotation of the feed motor 6 is controlled so that the current of the feed motor 4 becomes constant.

In step 206, the rotational speed detecting circuit 24
, The number of rotations of the feed motor 6 is detected. The rotation number detecting circuit 24 includes a cylindrical magnet 241 having four poles installed on the output shaft of the feed motor 6 and a magnet 241 on the housing.
Pickup 2 installed at a position facing the
42. Magnet pickup 242
The magnet 241 generated in synchronization with the rotation of the feed motor 6
The change of the magnetic field due to the
The rotation speed of the feed motor 6 is calculated by measuring the period. If the number of rotations of the feed motor 6 can be calculated, the feed speed can be calculated from the reduction ratio of the feed mechanism and the final gear diameter of the feed mechanism. Step 207
Then, the feed rate calculated by the above method is compared with a preset maximum feed rate (65 mm / min in the present embodiment). If the calculated feed rate is slower than the maximum feed rate,
In step 209, the rotation speed of the feed motor 6 is controlled. If the calculated feed rate is faster than the maximum feed rate,
In step 208, the feed speed set value is reset to the maximum feed speed, the number of revolutions of the feed motor 6 is controlled, and control is performed so that the feed speed does not exceed the maximum feed speed.

The set value may be a value stored in a memory device, a value set from the outside, or a value calculated according to a predetermined formula.

In step 210, the current of the main motor 4 is detected via the current detecting circuit 18, and it is compared whether the current of the main motor 4 has become equal to or less than a predetermined value (no load current Io + 2A). When the current of the main motor 4 has a predetermined value (Io +
2A) In the above case, the drilling is in progress and the process returns to step 205,
Continue drilling. When the current of the main motor 4 has a predetermined value (Io + 2
A) When the following conditions are satisfied, it is determined that the perforation has been completed, and the process proceeds to the next step.

When the completion of the perforation is detected, in step 211, the feed motor 6 and the main motor 4 are stopped to terminate the perforation.

Another embodiment according to the present invention will be described with reference to FIGS. 25 is a stepping motor as a feed motor, 15 is a DC power supply for the stepping motor, and 16 is a stepping motor driving element. FIG. 5 is a flowchart showing the control procedure of the present invention in FIG. Hereinafter, the operation of the circuit shown in FIG. 4 will be described according to the procedure of FIG. The start in FIG. 5 corresponds to a procedure in which the base 1 is fixed to concrete by the anchor bolt 2, the core bit 8 is fixed to the electric drill 5, and the power switch 10 is turned on. When the power switch 10 is turned on, the power circuit 20 operates, and the microcomputer 21 starts operating.

In step 501, when the microcomputer 21 starts operating, the microcomputer 21 transmits a drive signal of the main motor 4 to the semiconductor control element 13 in the order of the output port 215, the driver 22, and the ignition circuit 17 to rotate the main motor 4.

In step 502, the no-load current Io of the main motor 4 is detected via the current detection circuit 18 and stored in the microcomputer 21.

In step 503, the electric drill 5 is lowered at a constant speed (in this embodiment, 20 mm / min) by controlling the stepping motor 25. In this operation, a control signal is transmitted from the output port 217 in the microcomputer 21 to the stepping motor drive element 16, and the stepping motor 25 is driven.

In step 504, the current of the main motor 4 is detected via the current detection circuit 18, and the current of the main motor 4 is set to a predetermined value (in this embodiment, the previously detected no-load current Io
If + 2A) or more, it is determined that the core bit 8 has come into contact with the object to be drilled and has started drilling.

From now on, the current of the main motor 4 becomes constant value Ir
The drilling is performed by controlling the feed rate of the electric drill 5 so as to be ef. That is, the current of the main motor 4 is equal to the target value Ire.
If it is smaller than f, the rotation speed of the stepping motor 25 is increased, and if the current of the main motor 4 is larger than the target value Iref, the rotation speed of the stepping motor 25 is reduced so that the current of the main motor 4 is always constant. 25 rotations are controlled.

In step 505, the feed speed of the electric drill 5 is calculated so that the current of the main motor 4 becomes a constant value Iref. The stepping motor 25 is a motor that rotates by a fixed angle each time a driving pulse is given (0.9 degrees / pulse in this embodiment), and the feed speed is determined based on the reduction ratio of the feed mechanism and the final gear diameter of the feed mechanism. Can be calculated.

In step 507, the feed speed calculated by the above method is compared with a preset maximum feed speed (65 mm / min in this embodiment). When the calculated feed speed is lower than the maximum feed speed, the rotation speed of the stepping motor 25 is directly controlled. If the calculated feed speed is higher than the maximum feed speed, the feed speed set value is reset to the maximum feed speed in step 508, and the stepping motor 25 is set.
Is controlled so that the feed rate does not exceed the maximum feed rate.

In this embodiment, since the microcomputer 21 directly calculates the feed speed, the feed motor rotation speed detecting means is not required.

In step 509, the current of the main motor 4 is detected via the current detection circuit 18, and it is compared whether the current of the main motor 4 has become equal to or less than a predetermined value (no load current Io + 2A). When the current of the main motor 4 has a predetermined value (Io +
2A) In the case of the above, the drilling is being performed and the process returns to step 505,
Continue drilling. When the current of the main motor 4 has a predetermined value (Io + 2
A) When the following conditions are satisfied, it is determined that the perforation has been completed, and the process proceeds to the next step.

When the end of the perforation is detected, in step 510, the stepping motor 25 and the main motor 4 are stopped to terminate the perforation.

[0028]

According to the present invention, the upper limit is set on the feed speed of the electric drill during drilling, so that the feed speed does not become too high even with a small-diameter core bit and cutting water is not clogged, so that the drilling can be performed reliably. Can be.

[Brief description of the drawings]

FIG. 1 is a control circuit diagram of a concrete core drill according to the present invention.

FIG. 2 is a flowchart showing control of a concrete core drill according to the present invention.

FIG. 3 is an external perspective view of a concrete core drill according to the present invention.

FIG. 4 is a control circuit diagram showing another embodiment of the concrete core drill according to the present invention.

FIG. 5 is another flowchart showing the control of the concrete core drill according to the present invention.

[Explanation of symbols]

3 is a drill stand, 4 is a main motor, 5 is an electric drill,
6 is a feed motor, 8 is a core bit, 18 is a current detection circuit, 21 is a microcomputer, and 22 is a driver.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code Agency reference number FI Technical display location H02P 5/00 H02P 5/00 P

Claims (1)

[Claims] 1. An automatic feed concrete comprising a main motor for rotating a core bit, an electric drill incorporating the main motor, and a feed motor for moving the electric drill along a drill stand to perforate an object to be drilled. The core drill includes a current detection circuit that detects a current of the main motor, a rotation speed detection unit that detects a rotation speed of the feed motor, and a feed motor rotation speed control unit, and the main motor current is constant. An automatic feed concrete core drill characterized in that the number of revolutions of the feed motor is controlled as described above and an upper limit is set for the feed speed of the electric drill.