JPH10128690A - Electronic pressure switch and vacuum part sucking device using it - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect the quality of sucking a part with good accuracy by providing a differential operating means for operating a difference between a preceding initial pressure signal and a preceding pressure signal to output a differential signal, and comparing means for comparing the reference voltage with the differential signal to output a comparison signal. SOLUTION: When initial pressure is 'vacuum' and a differential pressure signal is zero, the judgement on part suction is 'good', and when the initial pressure is 'vacuum' and a differential signal is 'present', the judgement on part suction is 'bad', when the initial pressure is 'atmospheric pressure' and a differential signal is zero, the judgement on part suction is 'bad', and when the initial pressure is 'atmospheric pressure' and a differential pressure signal is 'present', the judgement on part suction is 'bad'. The initial pressure is detected by a comparator 33, the existence/absence of a differential signal is judged from the output of the comparator 31, and the quality of part suction is judged by AND gate 35.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic pressure switch for detecting the suction of a component by using a signal from a component suction section for detecting the presence or absence of a component suction as a pressure change in response to a supply of an original pressure. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum component suction device used, and more particularly, to an improved electronic pressure switch capable of detecting the presence / absence of component suction without being affected by a change in original pressure, and a vacuum component suction device using the same.

[0002]

2. Description of the Related Art FIG. 5 is a configuration diagram showing a configuration in which components are sucked using a conventional electronic pressure switch. The chamber 10 is connected to a vacuum pump 11 and has a plurality of vacuum suction nozzles, in this case, two vacuum suction nozzles 12, 1
3 are connected via pipes 14 and 15, respectively.

At the tips of the vacuum suction nozzles 12 and 13,
Parts 16 and 17 to be sucked are arranged, and their nozzle back pressures P _N1 and P _N2 are detected by pressure switches 20 and 21 via pipes 18 and 19.

[0004] A vacuum pump 11 evacuates the inside of the chamber 10 to a vacuum to obtain a vacuum source pressure P _A.
The liquid is supplied to the vacuum suction nozzles 12 and 13 via pipes 14 and 15 connected to the vacuum pump.

[0005] If the components 16 and 17 are not sucked by the vacuum suction nozzles 12 and 13, the pipe 1
Although the nozzle back pressures P _N1 and P _N2 generated at 8 and 19 are at atmospheric pressure, the vacuum suction nozzles 12 and 13
When 7 is adsorbed, the nozzle back pressures P _N1 and P _N2 become vacuum.

Each of the pressure switches 20 and 21 has, for example, a diffusion semiconductor piezo type pressure sensor or the like inside.
This pressure sensor converts the change in the nozzle back pressures P _N1 and P _N2 into a pressure signal which is an electric signal, and if necessary, for example, a range of 1 volt for atmospheric pressure P _{O and} a range of 5 volt for vacuum pressure P _V. To convert to and display pressure signals.

FIG. 6 is a circuit diagram showing a specific configuration of the pressure switch. In this case, it is assumed that the pressure switch 20 and the pressure switch 21 have the same configuration, and the configuration of the pressure switch 20 is representatively shown and the output signal is extracted as an on / off signal.

The pressure switch 20 has a pressure sensor 22, a comparator 23, a transistor 24, a potentiometer 25, and the like.
_N1 is converted into a pressure signal _SN1 .

In the comparator 23, the pressure signal S _N1 is applied to one end of an input terminal via a resistor R ₁ , and the reference voltage V _R is divided by a potentiometer 25 and applied to the other end as a set voltage V _S1. I have.

The transistor 24 is turned on / off with reference to the set voltage V _S1, and is output as an on / off signal S _D1 to an output terminal 26 connected to the collector. The on / off signal S _D1 appearing at the output terminal 26 is, if necessary,
It is displayed on a display or the like.

[0011]

However, the above-mentioned electronic pressure switch has the following problems. This problem will be described with reference to a characteristic diagram shown in FIG. In FIG. 7 (A), the horizontal axis represents time, the vertical axis represents respectively the nozzle back pressure P _N1, FIG. 7 (B) ON / OFF signal for the time corresponding to FIG. 7 (A) S _D1 Is shown. Here, P _S1 is the set voltage V _S1
Shows the nozzle back pressure corresponding to.

The range of the period T ₁ is, for example, a period in which only the vacuum suction nozzle 12 is operating and the vacuum suction nozzle 13 is at rest, and the range of the period T ₂ is a vacuum suction in addition to the operation of the vacuum suction nozzle 12. This shows a period when the nozzle 13 operates.

[0013] period in the range of T _1, the nozzle back pressure P _N1 in a state in which part 16 is not adsorbed (OFF) atmospheric pressure P
Becomes _0, when the adsorbed components 16 (ON) becomes a vacuum source pressure P _A, the nozzle back pressure P _S1 corresponding to the set voltage V _S1 during this time is present, the nozzle back pressure P _S1 As a boundary, the state of the on / off signal S _D1 changes and the device operates normally.

[0014] However, when transition to the state of the period T ₂ in which a vacuum suction nozzle 13 is operating in addition to the vacuum suction nozzle 12, by the operation, vacuum source pressure P _A in the Chiyanba 10 is decreased as shown , May move to a position exceeding the nozzle back pressure P _S1 .

[0015] involving such variations, even in the adsorption state of the component 16, the nozzle back pressure P _N1 is not a vacuum original pressure P _A, there is a problem that normal ON / OFF signal S _D1 is not output. In such a case, it becomes troublesome to reset the detection level by the potentiometer 25.

[0016]

According to the present invention, as a main structure for solving the above-mentioned problems, a suction of a component is detected based on information on a pressure change due to the presence or absence of a component suction when a source pressure is supplied. In an electronic pressure switch, a source pressure sensor that outputs the previous source pressure as a source pressure signal, a pressure sensor that outputs a previous pressure change as a pressure signal, and a difference between the source pressure signal and the source pressure signal. And a differential operation means for outputting a difference signal, and comparing the first reference voltage with the difference signal to obtain a first signal.
First comparison means for outputting a comparison signal, second comparison means for comparing the second reference voltage with the previous original pressure signal and outputting a second comparison signal, and a first comparison signal and a second second comparison signal; A logical sum operation means for receiving a comparison signal and calculating a logical sum of them is provided, and an output means for outputting an on / off signal driven by an output of the logical sum operation means. .

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows one embodiment of the present invention.
FIG. 2 is a configuration diagram showing a configuration in which components are sucked using the electronic pressure switch shown in FIG. In this case, an example is shown in which the source pressure sensor is provided outside the case, and the case is provided with an external input terminal from the source pressure sensor. Note that FIG.
Portions having the same functions as those of the components shown in FIG.

First, the configuration shown in FIG. 2 will be described.
In this case, outputs to the external input terminal 29 of the pressure switch 28 the original pressure sensor 27 is provided as the original pressure signal S _A which detects the vacuum original pressure P _A in chamber 10. On the other hand, the nozzle back pressure P _N2 generated in the pipe 18 is also applied to the pressure switch 28.

The pressure switch 28 performs a predetermined operation using the original pressure signal S _A and the nozzle back pressure P _N2 shown in FIG. To display.

Next, the above points will be specifically described with reference to the circuit configuration shown in FIG. The pressure sensor 22 receives the nozzle back pressure P _N2 from the vacuum suction nozzle 13 and converts the back pressure P _N2 into a pressure signal S _N2 , which is an electric signal, and outputs it.

The pressure signal S _N2 is _divided by the resistors R ₂ and R ₃ and output to the non-inverting input terminal (+) of the differential amplifier 30. The inverting input terminal of the differential amplifier 30 (-) is connected to the external input terminal 29 via a resistor R ₅ is connected via a resistor R ₄ to the output terminal.

The comparator 31, one of its input terminals to the output terminal of the differential amplifier 30, the other of dividing point obtained by dividing the reference voltage V _R by the potentiometer 32 are respectively connected.

Further, the comparator 33, to one external input terminal 29 of the input terminal, the other of dividing point obtained by dividing the reference voltage V _R at the potentiometer 34 are connected.

Each output terminal of the comparators 31 and 33 is connected to A
The ND gate 35 is connected to each input terminal, its output terminal is connected to the base of an open collector type transistor 36, its emitter is connected to the common potential point COM, and its collector is connected to the output terminal 37.

In the above configuration, the pressure switch 28 operates as follows. The differential amplifier 30 includes resistors R ₂ and R ₃
In a divided pressure signal S _N2, the difference between the resistance R ₄ and the resistor R ₅ in dividing the original pressure signal S _A and calculates and outputs to the comparator 31.

For this reason, in the normal state, if the original pressure signal S _A fluctuates, the differential pressure signal S _N2 ′ in which the fluctuation is corrected from the pressure signal S _N2 is obtained at the voltage dividing point of the potentiometer 32. The voltage is compared with the voltage and output to one of the input terminals of the AND gate 35.

However, if the original pressure signal S _A is reduced from the vacuum state to the atmospheric pressure, the nozzle back pressure P _N2 becomes the atmospheric pressure even if the component 16 is not sucked, and the differential pressure signal S _N2 ′ becomes zero, and an erroneous signal is output as if the component were being sucked.

Therefore, in order to detect such an abnormal state, a comparator 33 is provided to provide the original pressure signal S _A.
To monitor. That is, the comparator 33 compares the original pressure signal S _A with the set voltage V _S2 obtained at the voltage dividing point of the potentiometer 32 and outputs the same to the other input terminal of the AND gate 35.

If the original pressure signal S _A is at a level corresponding to vacuum, the comparator 33 outputs a high-level logic signal. If the original pressure signal S _A is at a level corresponding to atmospheric pressure, the comparator 33 outputs a low-level logic signal. By controlling the ON / OFF of the AND gate 35 with the output of the comparator 33, the ON / OFF signal _SD2 is output only when the nozzle back pressure _PN2 is normal.

To summarize the above points, when the original pressure P _A is “vacuum” and the differential pressure signal S _N2 ′ is “zero”, the judgment of the component suction is “good”, and when the original pressure P _A is “vacuum”. 'determination component suction when the is "Yes" is "No", the original pressure P _a is the pressure difference signal S _N2 at "atmospheric pressure"' differential pressure signal S _N2 determination CC suction when of "zero" is "No", the original pressure P _A is the differential pressure signal at "atmospheric pressure" S
_{When N2} 'is "Yes", the result of the component suction determination is "No".

The comparator 33 detects the original pressure P _A , the presence or absence of the differential pressure signal S _N2 ′ is the output of the comparator 31, and the quality of the component suction is determined by the AND gate 35.

The above points are shown in FIG. 3 corresponding to FIG. The horizontal axis represents time in FIG. 3, the vertical axis represents the differential pressure [Delta] P _N of the atmospheric pressure P _A and the nozzle back pressure. This differential pressure ΔP _N corresponds to the differential pressure signal S _{N 2} ′. ΔP _N2 is when there is a differential pressure,
ΔP _N0 indicates the case where the differential pressure is zero.

[0033] While the range of the period T ₁ in FIG. 3 shows a similar tendency to that shown in FIG. 7, the source pressure variation due to the differential amplifier 30 also shifts to the period T ₂ the source pressure variation occurs It can be seen from the compensation effect of (1) that the adsorption state is reliably detected.

FIG. 4 is a circuit diagram showing another embodiment of the present invention. In this case, the pressure switch 38 is shown as an example in which the original pressure sensor 39 and the pressure sensor 22 are housed in the same case. Other configurations and operations are the same as those shown in FIG.

Although the configuration shown in FIG. 1 has been described as a configuration in which the source pressure signal S _A from the source pressure sensor 27 is input to the external input terminal 29, the invention is not limited to this. The pressure sensor 22 may be provided with an external input terminal outside the case, and the pressure signal S _N2 may be introduced here.

[0036]

As described above, according to the first to fifth aspects of the present invention, as specifically described with the embodiments of the present invention,
Even if the original pressure fluctuates, it is detected and corrected, so that it does not affect the setting of the detection level, and it is not necessary to reset the detection level, and it is possible to accurately detect the quality of the component suction.

Further, since the original pressure itself is detected to determine whether or not the pressure is normal, and the transmission of the pressure signal is controlled based on the result, it is possible to more reliably and stably detect the quality of the component suction. Can be.

According to the second aspect of the present invention,
There is an advantage that it is possible to provide a vacuum component suction device capable of stably sucking components even when the inside of the chamber fluctuates from a vacuum state.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of the present invention.

FIG. 2 is a configuration diagram showing a configuration in which a component is sucked using the electronic pressure switch shown in FIG. 1;

FIG. 3 is a characteristic diagram for explaining the operation of the embodiment shown in FIG. 1;

FIG. 4 is a circuit diagram showing another embodiment of the present invention.

FIG. 5 is a configuration diagram illustrating a configuration for performing component suction using a conventional electronic pressure switch.

6 is a circuit diagram showing a configuration of the electronic pressure switch shown in FIG.

FIG. 7 is a characteristic diagram illustrating the operation of the electronic pressure switch shown in FIG.

[Explanation of symbols]

 Reference Signs List 10 Chamber 11 Vacuum pump 12, 13 Vacuum suction nozzle 16, 17 Parts 20, 21, 28 Pressure switch 22 Pressure sensor 23 Comparator 27, 39 Source pressure sensor 29 External input terminal 30 Differential amplifier

Claims (5)

[Claims] An electronic pressure switch for detecting suction of a component based on information on a pressure change due to presence / absence of component suction in response to supply of a source pressure and a source pressure sensor for outputting the source pressure as a source pressure signal. A pressure sensor that outputs the pressure change as a pressure signal, a differential operation unit that calculates a difference between the original pressure signal and the pressure signal and outputs a difference signal, and a first reference voltage and the difference signal. First comparing means for comparing and outputting a first comparison signal; second comparing means for comparing a second reference voltage with the original pressure signal to output a second comparison signal;
A logical sum operation means for receiving a comparison signal and the second comparison signal and calculating a logical sum of them is provided, and an output means for outputting an on / off signal driven by an output of the logical sum operation means. An electronic pressure switch, characterized in that: 2. An electronic pressure switch according to claim 1, a chamber for supplying said source pressure, a vacuum pump for evacuating the inside of said chamber, and said information being provided by receiving said source pressure. A vacuum component suction device comprising a vacuum suction nozzle. 3. An electronic pressure switch according to claim 1, wherein a pressure sensor is built in a case of said electronic pressure switch, and an external input terminal from said source pressure sensor is provided in said case. pressure switch. 4. The electronic pressure switch according to claim 1, wherein a source pressure sensor is built in a case of the electronic pressure switch, and an external input terminal from the pressure sensor is provided in the case. pressure switch. 5. The electronic pressure switch according to claim 1, wherein a pressure sensor is built in the case of the electronic pressure switch together with the original pressure sensor.