CN210536542U - Numerical control lathe protection circuit and alarm device and engraver - Google Patents
Numerical control lathe protection circuit and alarm device and engraver Download PDFInfo
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- CN210536542U CN210536542U CN201921423315.1U CN201921423315U CN210536542U CN 210536542 U CN210536542 U CN 210536542U CN 201921423315 U CN201921423315 U CN 201921423315U CN 210536542 U CN210536542 U CN 210536542U
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Abstract
The utility model provides a numerical control lathe protection circuit and alarm device and engraver. The protection circuit and the alarm device of the numerically controlled lathe comprise a current sensor, a control unit and a frequency conversion unit, wherein the current sensor is positioned on the power supply side of a three-phase motor and used for detecting at least one phase current; the control unit comprises a rectifying circuit, a low-pass circuit, a first power supply, a second power supply, a comparator, a first reference power supply and an electric control single-pole double-throw switch; the voltage value of the first power supply is greater than that of the second power supply; the first movable contact is connected with a first power supply, and the second movable contact is connected with a second power supply; when the output end of the comparator is at a low level, the static contact is connected with the first movable contact; when the output end of the comparator is at a high level, the fixed contact is connected with the second movable contact. The utility model discloses a real-time detection three-phase motor looks electric current leads to reduction three-phase motor and load rotational speed that can be automatic when the phase current is too high when material density is inhomogeneous, cutter rotational speed sets up in the scene such as mismatch with the work piece material, and then reduces the phase current, protects three-phase motor and load cutter.
Description
Technical Field
The utility model relates to an engraving process field particularly, relates to a numerical control lathe protection circuit and alarm device and engraver.
Background
The engraving machine is a drilling and milling combined machining machine in the machining principle, and is generally of a multipurpose gantry type framework. The general engraving machine is lighter, the moving speed and the feeding speed are faster than those of a machining center, a high-speed numerical control system is required, the rotating speed of a spindle is about 3000-30000RPM (abbreviation of Revolations Per Minute, namely revolution Per Minute, representing the rotating times of equipment Per Minute), especially for a finishing engraving machine, the spindle is required to work at 2-3 ten thousand RPM, the revolution precision is about 2 micrometers generally, otherwise, the phenomenon of cutter breakage is serious, and therefore the spindle needs to be powered, namely, the motor and the spindle are integrated.
The carving machine drives a cutter through an electric spindle rotating at a high speed, and a workpiece is carved into a desired shape or a desired line is carved on a target element through the cutter. The control system of the engraving machine generally comprises a numerical control system, a frequency converter and a high-speed electric spindle, wherein the electric spindle generally adjusts the power supply frequency of a three-phase motor based on a formula n of 60f/p, so as to adjust the rotation speed of the spindle, the higher the power supply frequency f is, the higher the rotation speed n of the three-phase motor is, the higher the rotation speed of the spindle is, and p is the number of magnetic pole pairs of the three-phase motor. Because the engraving machine has high rotation speed, when the engraving machine encounters the conditions of uneven material density, unmatched tool rotation speed and workpiece material and the like in the machining process, the load of the tool is increased, the current of the three-phase motor is increased, and when the current of the three-phase motor is too high, the three-phase motor and/or the tool are easily damaged, even the tool is broken and other accidents are easily caused, so that the tool and the three-phase motor are necessarily protected.
SUMMERY OF THE UTILITY MODEL
In order to overcome the defects existing in the prior art, the utility model aims to provide a numerical control lathe protection circuit and alarm device and engraver.
In order to achieve the above object of the present invention, according to a first aspect of the present invention, the present invention provides a protection circuit and alarm device for a numerically controlled lathe, comprising a current sensor, a control unit and a frequency conversion unit, which are located on the power supply side of a three-phase motor and detect at least one phase current;
the output end of the current sensor is connected with a first signal input end of the control unit, the first output end of the control unit is connected with a frequency regulation and control end of the frequency conversion unit, the input end of the frequency conversion unit is connected with an alternating current power supply, and the output end of the frequency conversion unit is connected with a power supply end of the three-phase motor; a motor shaft of the three-phase motor is in transmission connection with a load;
the control unit comprises a rectifying circuit, a low-pass circuit, a first power supply, a second power supply, a comparator, a first reference power supply and an electric control single-pole double-throw switch;
the voltage value of the first power supply is greater than that of the second power supply; the fixed contact of the electric control single-pole double-throw switch is connected with the frequency regulation and control end of the frequency conversion unit, the first movable contact of the electric control single-pole double-throw switch is connected with a first power supply, and the second movable contact of the electric control single-pole double-throw switch is connected with a second power supply;
the output end of the current sensor is connected with the input end of the rectifying circuit, the output end of the rectifying circuit is connected with the input end of the low-pass circuit, the output end of the low-pass circuit is connected with the positive input end of the comparator, and the negative input end of the comparator is connected with the output end of the first reference power supply; the output end of the comparator is connected with the control end of the electric control single-pole double-throw switch to control the static contact of the electric control single-pole double-throw switch to be communicated with the first movable contact or the second movable contact;
when the output end of the comparator is at a low level, the fixed contact of the electric control single-pole double-throw switch is connected with the first movable contact;
when the output end of the comparator is at a high level, the fixed contact of the electric control single-pole double-throw switch is connected with the second movable contact.
The beneficial effects of the above technical scheme are: the phase current of the three-phase motor is monitored in real time through a current sensor, an alternating current voltage signal corresponding to the phase current is output, the alternating current voltage signal is converted into direct current voltage after passing through a rectifying circuit and a low-pass circuit, the direct current voltage is compared with the output voltage of a first reference power supply, when the direct current voltage is greater than the output voltage of the first reference power supply, the phase current is considered to be overlarge, the output end of a comparator is changed from low level to high level, the frequency regulation end of a frequency conversion unit is changed from being connected with a first movable contact to being connected with a second movable contact, the voltage input by the frequency regulation end of a frequency conversion unit is reduced, the frequency of a power supply of the motor is reduced, the rotating speed of the motor is reduced according to a formula n which is 60f/p, the rotating speed of the motor is reduced, the phase current is reduced along with the rotating speed of the motor, thereby protecting the load from breakage or other damage; therefore, the utility model discloses a real-time detection three-phase motor looks electric current can reduce three-phase motor and load rotational speed automatically when leading to the phase current too high in scenes such as material density is inhomogeneous, cutter rotational speed setting and workpiece material mismatch, and then reduces the phase current, protects three-phase motor and load cutter.
In a preferred embodiment of the present invention, the voltage value of the output terminal of the first reference power source is greater than the voltage value of the output terminal of the current sensor when the rated current of the three-phase motor is reached.
The beneficial effects of the above technical scheme are: the first reference power supply output voltage is set in a proper mode and is related to the rated current, so that the three-phase motor can work in a rated range, the motor is effectively protected, and the service life is prolonged.
In a preferred embodiment of the present invention, the control unit further includes a first resistor and a second resistor, the first end of the first resistor is connected to the first power supply, the second end of the first resistor is connected to the first end of the second resistor, the second end of the second resistor is connected to ground, and the second power supply is a connection terminal led out from the second end of the first resistor or the first end of the second resistor or a wire between the two.
The beneficial effects of the above technical scheme are: the second power supply is obtained from the first power supply through the resistance voltage division network, so that the circuit is simplified, and the cost is saved.
The utility model discloses an in a preferred embodiment, still include alarm unit, alarm unit's start-up end is connected with the first output of the control unit.
The beneficial effects of the above technical scheme are: the rotating speed of the three-phase motor is automatically adjusted, and meanwhile, an alarm is given to a worker, so that the worker can pay attention to, know the actual situation and process the actual situation in time.
In a preferred embodiment of the present invention, the alarm unit includes an intermediate relay, a current relay, and an alarm;
the first end of auxiliary relay coil is connected with the first output of control unit, the second end of auxiliary relay coil is connected with ground, the movable contact point that auxiliary relay normally opened the contact is connected with the commercial power live wire, the stationary contact point that auxiliary relay normally opened the contact is connected with the first end of current relay coil, the second end of current relay coil is connected with commercial power zero line, the stationary contact point that current relay normally opened the contact is connected with the power supply end of attention device, the earthing terminal and the commercial power zero line of attention device are connected, the stationary contact point that current relay normally opened the contact is connected with the commercial power live wire.
The beneficial effects of the above technical scheme are: the alarm unit has the advantages that the specific structure of the alarm unit is disclosed, the weak-to-strong current control is realized through the intermediate relay, the alarm powered by the mains supply is used, the power is high, the alarm effect is obvious, and the alarm unit is particularly suitable for being applied to operation places with high noise, such as a machining center and the like.
In a preferred embodiment of the present invention, the warning device includes a buzzer and/or a warning light.
The beneficial effects of the above technical scheme are: the specific form of the warning indicator is disclosed, and the sound and light alarm can be timely detected by workers.
In a preferred embodiment of the present invention, the load is a drill or a milling cutter.
The beneficial effects of the above technical scheme are: the drill bit or the milling cutter can be effectively protected, and the cutter breakage is avoided.
In order to realize the above-mentioned purpose of the utility model, according to the utility model discloses a second aspect, the utility model provides an engraver, include numerical control lathe protection circuit and alarm device, the load is engraving tool.
The beneficial effects of the above technical scheme are: except having numerical control lathe protection circuit and alarm device's beneficial effect, the protection cutter that this engraver can be fine avoids in the course of working, when loading is too big, damages the cutter, has saved the cost.
Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
Drawings
The disclosure of the present invention is explained with reference to the drawings. It is to be understood that the drawings are designed solely for the purposes of illustration and not as a definition of the limits of the invention. In the drawings, like reference numerals are used to refer to like parts. Wherein:
fig. 1 is a block diagram of the general structure of a numerically controlled lathe protection circuit and an alarm device according to a preferred embodiment of the present invention;
fig. 2 is a first specific structural diagram of a numerically controlled lathe protection circuit and an alarm device according to a preferred embodiment of the present invention;
fig. 3 is a schematic diagram of a second specific structure of a numerically controlled lathe protection circuit and an alarm device according to a preferred embodiment of the present invention;
FIG. 4 is a schematic diagram of a medium low pass circuit according to a preferred embodiment of the present invention;
fig. 5 is a schematic structural diagram of an alarm circuit in a preferred embodiment of the present invention;
fig. 6 is a schematic view of a part of the structure of the protection circuit and the alarm device of the numerically controlled lathe in the application scenario of the present invention.
Detailed Description
It is easily understood that, according to the technical solution of the present invention, a plurality of alternative structural modes and implementation modes can be proposed by those skilled in the art without changing the spirit of the present invention. Therefore, the following detailed description and the accompanying drawings are merely illustrative of the technical solutions of the present invention, and should not be considered as limiting or restricting the technical solutions of the present invention in their entirety or in any other way.
The utility model discloses a numerical control lathe protection circuit and alarm device, the structural block diagram of which is shown in figure 1, in a preferred embodiment, the partial structural schematic diagram of the numerical control lathe protection circuit and alarm device is shown in figure 2, and the numerical control lathe protection circuit and alarm device comprises a current sensor, a control unit and a frequency conversion unit which are positioned at the power supply side of a three-phase motor and used for detecting at least one phase current;
the output end of the current sensor is connected with the first signal input end of the control unit, the first output end of the control unit is connected with the frequency regulation and control end of the frequency conversion unit, the input end of the frequency conversion unit is connected with an alternating current power supply, and the output end of the frequency conversion unit is connected with the power supply end of the three-phase motor; a motor shaft of the three-phase motor is connected with a load in a transmission way;
the control unit comprises a rectifying circuit, a low-pass circuit, a first power supply, a second power supply, a comparator, a first reference power supply and an electric control single-pole double-throw switch;
the voltage value of the first power supply is greater than that of the second power supply; the fixed contact of the electric control single-pole double-throw switch is connected with the frequency regulation and control end of the frequency conversion unit, the first movable contact of the electric control single-pole double-throw switch is connected with a first power supply, and the second movable contact of the electric control single-pole double-throw switch is connected with a second power supply;
the output end of the current sensor is connected with the input end of the rectifying circuit, the output end of the rectifying circuit is connected with the input end of the low-pass circuit, the output end of the low-pass circuit is connected with the positive input end of the comparator, and the negative input end of the comparator is connected with the output end of the first reference power supply; the output end of the comparator is connected with the control end of the electric control single-pole double-throw switch to control the static contact of the electric control single-pole double-throw switch to be communicated with the first movable contact or the second movable contact;
when the output end of the comparator is at a low level, the fixed contact of the electric control single-pole double-throw switch is connected with the first movable contact;
when the output end of the comparator is at a high level, the fixed contact of the electric control single-pole double-throw switch is connected with the second movable contact.
In this embodiment, the current sensor is preferably, but not limited to, a voltage output current sensor, such as 10 may be an open current transformer available from Yuanxing electronics corporation, model CTSA005, or a high-rating Hall current sensor available from Chilean, Inc., model HKA-YSD. The rectifying circuit can be a diode full-wave rectifying bridge circuit or a diode half-wave rectifying bridge circuit in the conventional technology in the field, preferably, an integrated rectifying chip can be selected, such as an RS501 chip or an RS502 chip, and a specific connecting circuit can refer to a chip data manual, which is not described herein again. The low-pass circuit preferably adopts a low-cost RC passive low-pass filter circuit, and a specific circuit structure of the low-pass circuit can be shown in fig. 4, a capacitance value of C1 is preferably a uF level, such as 4.7uF or 10uF, a cutoff frequency is preferably set to be less than 50Hz, so as to suppress a commercial power frequency component, and a specific resistance value of R3 is selected as a conventional design in the art and is not described herein again.
In this embodiment, in the low-pass circuit shown in fig. 4, a voltage-adjusting resistor is preferably connected in parallel to each end of the capacitor C1, and forms a voltage-dividing network with the resistor R3, so as to adjust the voltage at the output end of the low-pass circuit to match the voltage range at the positive input end of the comparator.
In this embodiment, the comparator is preferably, but not limited to, LM 324. The first reference power supply can be a voltage reference chip provided by companies such as TI or ADI, and the specific circuit structure can be referred to the technical manual of the voltage reference chip, which is not described herein again. Furthermore, the method is simple. The selection of the voltage of the output end of the voltage reference chip is related to the output voltage range of the output end of the low-pass circuit and is larger than the maximum voltage value of the output end of the low-pass circuit in a normal working state (the rotating speed of the three-phase motor is set reasonably, the material of a processed workpiece is uniform, or the phase current is smaller than the rated phase current), so that the comparator can respond to the abnormal increase of the phase current in time to output a high level.
In the present embodiment, the specific circuit structure of the frequency conversion unit is preferably, but not limited to, the technical solution disclosed in the patent with reference to publication number CN202076987U, which can adopt analog voltage input as a frequency adjustment mode. The EH600M series of XiLin electrics can also be selected, the frequency can be set by 0-10V analog quantity, and the analog quantity voltage for adjusting the frequency is positively correlated with the frequency, specifically referring to the user manual. In this embodiment, the first power supply and the second power supply can select a reference voltage source chip with an output voltage not higher than 10V and its peripheral circuits, for example, the first power supply can select a 10V precision voltage reference with a model REF102AP, and the first power supply can select a 5V precision voltage reference with a model REF02AP, and for a specific connection circuit, please refer to a chip manual, which is not described herein again.
In this embodiment, the electrically controlled single-pole double-throw switch is preferably, but not limited to, an spdt (single poledblethreow) switch, and the model thereof may be SKYA21038, and please refer to the chip manual for specific circuit connection, which is not described herein again.
In a preferred embodiment, the voltage value at the output of the first reference power source is greater than the voltage value at the output of the current sensor when the rated current of the three-phase motor is reached.
In the present embodiment, the three-phase motor model is preferably, but not limited to, a three-phase motor rated current of 1.5KW of the engraving machine spindle is 3A.
In a preferred embodiment, as shown in fig. 3, the control unit further includes a first resistor R1 and a second resistor R2, a first end of the first resistor R1 is connected to the first power source, a second end of the first resistor R1 is connected to a first end of the second resistor R2, a second end of the second resistor R2 is connected to ground, and the second power source is a connection terminal led out from a second end of the first resistor R1 or a first end of the second resistor R2 or a wire between the two.
In a preferred embodiment, the device further comprises an alarm unit, and the starting end of the alarm unit is connected with the first output end of the control unit.
In a preferred embodiment, as shown in fig. 5, the alarm unit includes an intermediate relay KT, a current relay KA, and an alarm;
the first end of auxiliary relay coil KT is connected with the first output of control unit, the second end of auxiliary relay KT coil is connected with ground, the movable contact and the commercial power live wire L of auxiliary relay KT normally open contact are connected, the stationary contact and the first end of current relay KA coil of auxiliary relay KT normally open contact are connected, the second end and the commercial power zero line N of current relay KA coil are connected, the stationary contact and the power supply end of attention device of current relay KA normally open contact are connected, the earthing terminal and the commercial power zero line N of attention device are connected, the stationary contact and the commercial power live wire L of current relay KA normally open contact are connected.
In a preferred embodiment, the warning device comprises a buzzer and/or a warning light.
In a preferred embodiment, the load is a drill or a milling cutter.
The utility model discloses an in the applied scene, as shown in FIG. 6, the control unit chooses for use intelligent electrical control instrument, is A6011 intelligent instrument like the model, directly accomplishes current sensor output signal collection, suggestion unit control etc. through A6011.
The utility model also discloses an engraver, include numerical control lathe protection circuit and alarm device, the load is engraving tool.
In the description herein, references to the description of the term "one embodiment," "some embodiments," "an example," "a specific example," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
While embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.
Claims (8)
1. A numerical control lathe protection circuit and an alarm device are characterized by comprising a current sensor, a control unit and a frequency conversion unit, wherein the current sensor is positioned on the power supply side of a three-phase motor and used for detecting at least one phase of current;
the output end of the current sensor is connected with a first signal input end of the control unit, the first output end of the control unit is connected with a frequency regulation and control end of the frequency conversion unit, the input end of the frequency conversion unit is connected with an alternating current power supply, and the output end of the frequency conversion unit is connected with a power supply end of the three-phase motor; a motor shaft of the three-phase motor is in transmission connection with a load;
the control unit comprises a rectifying circuit, a low-pass circuit, a first power supply, a second power supply, a comparator, a first reference power supply and an electric control single-pole double-throw switch;
the voltage value of the first power supply is greater than that of the second power supply; the fixed contact of the electric control single-pole double-throw switch is connected with the frequency regulation and control end of the frequency conversion unit, the first movable contact of the electric control single-pole double-throw switch is connected with a first power supply, and the second movable contact of the electric control single-pole double-throw switch is connected with a second power supply;
the output end of the current sensor is connected with the input end of the rectifying circuit, the output end of the rectifying circuit is connected with the input end of the low-pass circuit, the output end of the low-pass circuit is connected with the positive input end of the comparator, and the negative input end of the comparator is connected with the output end of the first reference power supply; the output end of the comparator is connected with the control end of the electric control single-pole double-throw switch to control the static contact of the electric control single-pole double-throw switch to be communicated with the first movable contact or the second movable contact;
when the output end of the comparator is at a low level, the fixed contact of the electric control single-pole double-throw switch is connected with the first movable contact;
when the output end of the comparator is at a high level, the fixed contact of the electric control single-pole double-throw switch is connected with the second movable contact.
2. The numerical control lathe protection circuit and alarm device according to claim 1, wherein the voltage value at the output terminal of the first reference power supply is larger than the voltage value at the output terminal of the current sensor when the rated current of the three-phase motor is reached.
3. The numerical control lathe protection circuit and alarm device according to claim 1, wherein the control unit further comprises a first resistor and a second resistor, a first end of the first resistor is connected with a first power supply, a second end of the first resistor is connected with a first end of the second resistor, a second end of the second resistor is connected with the ground, and the second power supply is a connection terminal led out from a second end of the first resistor or a first end of the second resistor or a lead between the second end of the first resistor and the first end of the second resistor.
4. The numerical control lathe protection circuit and alarm device according to claim 1, further comprising an alarm unit, wherein the starting end of the alarm unit is connected with the first output end of the control unit.
5. The numerically controlled lathe protection circuit and alarm device according to claim 4, wherein the alarm unit includes an intermediate relay, a current relay, and an alarm;
the first end of auxiliary relay coil is connected with the first output of control unit, the second end of auxiliary relay coil is connected with ground, the movable contact point that auxiliary relay normally opened the contact is connected with the commercial power live wire, the stationary contact point that auxiliary relay normally opened the contact is connected with the first end of current relay coil, the second end of current relay coil is connected with commercial power zero line, the stationary contact point that current relay normally opened the contact is connected with the power supply end of attention device, the earthing terminal and the commercial power zero line of attention device are connected, the stationary contact point that current relay normally opened the contact is connected with the commercial power live wire.
6. The numerically controlled lathe protection circuit and alarm device according to claim 5, wherein the alarm comprises a buzzer and/or an alarm lamp.
7. The numerically controlled lathe protection circuit and alarm device as claimed in claim 1, wherein the load is a drill or a milling cutter.
8. An engraving machine, characterized by further comprising a numerically controlled lathe protection circuit and an alarm device according to any one of claims 1 to 7, wherein the load is an engraving tool.
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| CN201921423315.1U CN210536542U (en) | 2019-08-29 | 2019-08-29 | Numerical control lathe protection circuit and alarm device and engraver |
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| CN201921423315.1U CN210536542U (en) | 2019-08-29 | 2019-08-29 | Numerical control lathe protection circuit and alarm device and engraver |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113021514A (en) * | 2021-05-28 | 2021-06-25 | 苏州维嘉科技股份有限公司 | Machining device, method for improving machining quality of machining device, and machining equipment |
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2019
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113021514A (en) * | 2021-05-28 | 2021-06-25 | 苏州维嘉科技股份有限公司 | Machining device, method for improving machining quality of machining device, and machining equipment |
| CN113021514B (en) * | 2021-05-28 | 2021-09-14 | 苏州维嘉科技股份有限公司 | Machining device, method for improving machining quality of machining device, and machining equipment |
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