JPH0524286U - Pickup completion detection device in parts pickup device - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the reliability of detection of suction completion when suctioning a component by the suction nozzle. [Configuration] In general, when the exhaust pump is operated in a state where the adsorption nozzle is not blocked, the air pressure in the exhaust path suddenly decreases and gradually changes to approach a certain saturation value. The measured rate of change of air pressure gradually decreases. Therefore, the pressure change rate detecting means 20
When it is detected that the rate of change of the air pressure has become equal to or lower than the predetermined value, the reference value setting means 10 determines the measured value at the time when the rate of change becomes equal to or lower than the predetermined value in accordance with the measured value of the pressure sensor 4. The reference value is set as a value obtained by multiplying the predetermined magnification.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a suction completion detecting device for a component suction device, which detects whether or not a suction target component is sucked by a suction nozzle by utilizing a change in air pressure.

[0002]

[Prior Art]

 The component suction device is used, for example, in an automatic assembly robot to pick up electronic components and components such as screws supplied from a feeder one by one and convey them to a predetermined mounting site. This consists of an adsorption nozzle attached to the tip of the arm, and the adsorption nozzle is connected to an exhaust pump via an intake tube.The arm is swiveled while the exhaust pump is operating to make the adsorption nozzle part of the feeder. It goes to the supply point, where the component to be attracted is adsorbed by the adsorption nozzle, and in that state the arm is rotated to convey the adsorbed component to the mounting site such as a printed circuit board.

In such an apparatus, in order to prevent the occurrence of defects due to component mounting mistakes as much as possible, it is necessary to detect whether or not the component has been reliably sucked by the suction nozzle and proceed with the sequence. For this reason, a suction completion detecting device has been developed which detects whether or not a component has been sucked by a suction nozzle by utilizing a change in air pressure.

Conventionally, this type of adsorption completion detecting device measures the air pressure at a predetermined portion of the exhaust passage from the adsorption nozzle to the exhaust pump with a pressure sensor, and compares the measured value with a preset reference value. The configuration is such that when the measured air pressure drops below the reference pressure, it is considered that the suction of parts to the suction nozzle is completed.

The detection principle is as shown in FIG. 7, and utilizes that the measured air pressure in the exhaust path sharply decreases (the degree of vacuum increases) when a component is adsorbed. That is, when the exhaust pump is started (time T0) while the suction nozzle is not blocked, the air pressure in the exhaust path drops sharply from the atmospheric pressure as shown in the figure, and the leak or exhaust gas in the exhaust path gradually increases. It approaches a saturation value determined by the flow path resistance of the air passage. Then, when a component is adsorbed to the suction nozzle (time T1), the suction nozzle is blocked and the inflow of air is blocked, so the measured air pressure drops sharply again and the exhaust pump capacity and exhaust It approaches the next saturation value, which is determined by the amount of leak on the route. Therefore, if the air pressure close to the saturation value is set as the reference value R, the component suction can be detected.

[0006]

[Problems to be solved by the device]

 However, the above-mentioned conventional configuration has the following drawbacks. In other words, the exhaust capacity of the exhaust pump varies slightly during operation due to various factors. Also, the amount of leak in the exhaust path and the flow path resistance are not necessarily constant. For this reason, it is inevitable that the air pressure indicated when the component is sucked by the suction nozzle slightly fluctuates. However, in the conventional configuration, the reference value R for determining whether or not adsorption has been performed is set as a fixed value, and therefore misjudgment may occur under various conditions, and adsorption is completed. There was a demand for even higher detection reliability.

Therefore, an object of the present invention is to provide a suction completion detection device in a component suction device that can improve the reliability of the suction completion detection of a component.

[0008]

[Means for Solving the Problems]

 The suction completion detecting device in the component suction device of the present invention is a component suction device including a suction nozzle for suctioning a suction target component and an exhaust pump for sucking air through the suction nozzle. In a suction completion detection device that measures the air pressure at a predetermined location in the exhaust path to the exhaust pump with a pressure sensor and compares the measured value with a predetermined reference value to detect the completion of suction of the suction target component to the suction nozzle. , The pressure change rate detecting means for detecting that the change rate of the air pressure measured by the pressure sensor is below a predetermined value is provided, and the pressure change rate is below the predetermined value by this pressure change rate detecting means. It is characterized in that reference value setting means for setting the reference value in accordance with the measured value by the pressure sensor is provided on the condition that is detected.

[0009]

[Action]

 Generally, when the exhaust pump is operated with the suction nozzle not blocked, the air pressure in the exhaust path drops rapidly and gradually approaches a certain saturation value. The rate gradually decreases.

Therefore, according to the above means, when the pressure change rate detecting means detects that the change rate of the air pressure is less than or equal to the predetermined value, the reference value setting means responds to the measured value of the pressure sensor ( For example, the reference value is set as a value obtained by adding a predetermined value to the measured value at the time when the rate of change becomes equal to or lower than the predetermined value, or as a value obtained by multiplying the measured value at that time by a predetermined magnification.

Therefore, the air pressure indicated when a component is adsorbed by the adsorption nozzle fluctuates due to various fluctuation factors such as fluctuations in the exhaust capacity of the exhaust pump, fluctuations in the leak amount in the exhaust path, fluctuations in the flow path resistance, and the like. However, even if there is, the reference value also fluctuates, so that such fluctuation can be offset and the reliability of the adsorption completion detection can be increased.

[0012]

【Example】

 An embodiment of the present invention will be described below with reference to FIGS.

First, the component suction device according to the present embodiment will be briefly described as shown in FIG. 5. As with a normal device, for example, a suction nozzle 1 attached to an arm of an automatic assembly robot and a suction nozzle 1 And an exhaust pump 3 connected via an intake tube 2 to a component, for example, the head of a screw supplied from a feeder (not shown) is adsorbed to the tip of the adsorption nozzle 1, and the arm is swung in that state to adsorb The screw is transported to a fixed position.

A pressure sensor 4 for measuring the air pressure of the portion 5 is provided at a predetermined portion 5 of the exhaust path from the adsorption nozzle 1 to the exhaust pump 3, and a signal from this is provided to the adsorption completion detecting device. It is like this.

Now, the adsorption completion detecting device has a configuration as shown in FIG. As shown in the figure, the signal from the pressure sensor 4 is amplified by the amplifier 6a, from which the pressure measurement voltage Vx corresponding to the measured air pressure is output and given to the comparator 7. This pressure measuring voltage Vx is compared with a reference voltage Vref set by a reference value setting means 10 which will be described later by a comparator 7, and based on the comparison result, whether or not a screw which is a component is sucked by the suction nozzle 1 is determined. Is detected. When the pressure change rate detecting means 20, which will be described later, detects that the pressure change rate of the air pressure measured by the pressure sensor 4 has become less than or equal to a predetermined value, the reference value setting means 10 detects the pressure sensor 4 at that time. The reference voltage Vref is set by multiplying the pressure measurement voltage from (3) by a predetermined magnification A.

Hereinafter, each means 10, 20 will be described in detail.

(A) Pressure change rate detecting means 20 The signal from the pressure sensor 4 is supplied to the sample hold circuit 24a including the analog switches 21a and 21b, the capacitors 22a and 22b and the non-inverting amplifiers 23a and 23b via the amplifier 6a. , 24b. The sampling pulses Spa and Spb for operating these sample hold circuits 24a and 24b are generated by combining the oscillator circuit 25, the D type flip-flop 26 and the AND gates 27 and 28 as shown in FIG. As shown, it is output at the timing when it becomes "H" (high level) alternately. Therefore, the sample and hold circuits 24a and 24b alternately sample the pressure measurement voltage from the pressure sensor 4 in time.

The pressure measurement voltage sampled by the sample and hold circuit 24 a is inverted and amplified by the inverting amplifier 29 and applied to the non-inverting input terminal of the comparator 30. The pressure measurement voltage sampled by the sample and hold circuit 24b is amplified by the inverting amplifier 31 and applied to the inverting input terminal of the comparator 30. In the inverting amplifier 31, the pressure measurement voltage from the sample and hold circuit 24b is added by a predetermined addition voltage ΔV determined by the values of the resistor 32 and the variable resistor 33 and inverted and amplified.

In the above structure, the pressure measurement voltage from the pressure sensor 4 changes as shown in FIG. 2 by operating the exhaust pump 3, and the sampling and holding circuits 24a and 24b perform sampling as shown in FIG. It is assumed that the pulses Spa and Spb are given. Then, first, at time t1, the sample-hold circuit 24b samples the pressure measurement voltage Va from the pressure sensor 4, and the added voltage ΔV is added to the sampled voltage Va, and the inverted and amplified voltage value VA is inverted by the comparator 30. It is given to the input terminal.

Next, at time t2, the pressure measurement voltage Vb from the pressure sensor 4 is sampled by the sample hold circuit 24a, and a voltage value VB obtained by inverting and amplifying this is given to the non-inverting input terminal of the comparator 30. Be done.

Here, the added voltage ΔV is set to be smaller than the change amount of the pressure measurement voltage between the sampling pulses Spa and Spb in consideration of the change rate of the pressure measurement voltage at the beginning of the operation of the exhaust pump 3. If set, the voltage value VB becomes lower than the voltage value VA (see FIG. 2), so that the output signal of the comparator 30 becomes "L" (low level). The D-type flip-flop 34, to which the output signal of the comparator 30 is applied to the data terminal D, latches the output signal in synchronization with the falling edge of the sampling pulse Spa received via the inverter gate 35, The output terminal Q of the D-type flip-flop 34 becomes "L".

After that, the pressure measurement voltage is sampled at times t3 and t4. As described above, the voltage value VB becomes lower than the voltage value VA as shown in FIG. The output signal and the output terminal Q of the D-type flip-flop 34 maintain "L".

Then, when the air pressure in the exhaust path approaches the saturation region and the rate of change thereof becomes smaller, the difference between the pressure measurement voltages from the pressure sensor 4 sampled by the sample hold circuits 24a and 24b becomes smaller. That is, the value of the pressure measurement voltage Vd at the time t6 in FIG. 2 has a small difference from the value of the pressure measurement voltage Vc at the time t5 because the rate of change of the air pressure is small, and the voltage value applied to the comparator 30 is small. VB becomes higher than the amplified voltage value VA including the added voltage ΔV. Therefore, the output terminal Q of the D type flip-flop 34 is inverted to "H" in synchronization with the fall of the sampling pulse Spa.

In this way, the pressure change rate detecting means 20 sets the output terminal Q of the D type flip-flop 34 to “H” when the change rate of the atmospheric pressure measured by the pressure sensor 4 becomes a predetermined value or less. It is inverted and the low change rate detection signal Ss is output.

(B) Reference value setting means 10 This is a hold circuit 14 having an analog switch 11, an inverter gate 12 and a capacitor 13, and a non-inverting amplifier 18 having an operational amplifier 15, a resistor 16 and a variable resistor 17. Consists of. In the hold circuit 14, the input side of the inverter gate 12 is connected to the output terminal Q of the D type flip-flop 34 which is the output of the pressure change rate detecting means 20. Therefore, when the change rate of the atmospheric pressure measured by the pressure sensor 4 becomes a predetermined value or less and the output terminal Q 1 of the D type flip-flop 34 becomes "H", the analog switch 11 is set to high impedance and the pressure measurement at that time is made. The voltage Vx is stored in the capacitor 13 of the hold circuit 14.

On the other hand, the non-inverting amplifier 18 amplifies the pressure measurement voltage stored in the capacitor 13 of the hold circuit 14 and supplies it to the comparator 7 as a reference voltage Vref. The amplification factor A can be adjusted by the variable resistor 17, and is set to 1 or more, for example, 1 to 1.5.

The output terminal of the comparator 7 is connected to the data terminal D of the D type flip-flop 36, and the adsorption completion signal S c (“L”) is output from the output terminal Q of the D type flip-flop 36. It has become. The D-type flip-flop 36 receives the low change rate detection signal Ss from the D-type flip-flop 34 of the pressure change rate detecting means 20 through its on-delay circuit 37 at its clock terminal. Then, the output signal of the comparator 7 is read after a lapse of a predetermined time period after the pressure change rate detecting means 20 detects that the change rate of the air pressure measured by the pressure sensor 4 becomes equal to or less than a predetermined value. It is designed to output.

Now, the operation of the present embodiment when the component suction device sucks a screw, for example, will be described.

When air is sucked by the exhaust pump 3 in a state where the suction nozzle 1 is not blocked, the air pressure in the exhaust passage measured by the pressure sensor 4 initially sharply decreases as shown in FIG. However, the degree of decline gradually becomes gradual. Therefore, when the rate of change of the air pressure measured by the pressure sensor 4 becomes equal to or lower than a predetermined value (see time t6 in FIG. 2), the output terminal Q of the D type flip-flop 34 of the pressure change rate detecting means 20. Becomes "H" and the low change rate detection signal Ss is output. Then, the reference value setting means 10 multiplies the pressure measurement voltage Vx at the time t6 by a predetermined multiplication factor A (determined by the amplification factor of the non-inverting amplifier 18) and outputs it as the reference voltage Vref to the comparator 7.

After this, when the screw is adsorbed by the adsorption nozzle 1 (time t7 in FIG. 3), the pressure measurement voltage Vx increases again (measurement air pressure decreases), so the pressure measurement voltage Vx becomes the reference. When the voltage exceeds the voltage Vref, the comparator 7 starts to shift from "H" to "L". Then, after a lapse of a predetermined time (time t9) from the output of the low change rate detection signal Ss, the output of the on-delay circuit 37 becomes "H", so that the output of the comparator 7 at that time is the D-type flip-flop. It appears at the output terminal Q of the amplifier 36.

In this case, if the screws are stably adsorbed by the adsorption nozzle 1, the output of the comparator 7 is maintained at “L” even at time t9 as shown in FIG. The adsorption completion signal Sc of "L" is output to the output terminal Q of the ip flip-flop 36. Further, when the screw is once adsorbed by the adsorption nozzle 1 but is dropped, the pressure measurement voltage Vx changes as shown in FIG. 4 (a drop occurs at time t8). .. Therefore, in this case, since the output of the comparator 7 becomes "H" after the time t8, at the time t9 when the output of the on-delay circuit 37 becomes "H", the output terminal Q of the D type flip-flop 36 becomes. Becomes "H" and the adsorption completion signal Sc is not output.

As described above, according to the present embodiment, the reference voltage Vref in the comparator 7, which serves as a reference for determining the suction state of the component such as the screw to the suction nozzle 1, is changed by the pressure change rate detecting means 20. It is set as a value obtained by multiplying the pressure measurement voltage Vx at the time when it is detected that the rate becomes equal to or less than a predetermined value by a predetermined magnification. Therefore, it is said that the air pressure indicated when the screw is adsorbed by the adsorption nozzle 1 varies due to various variation factors such as the variation of the exhaust capacity of the exhaust pump 3, the leakage amount of the exhaust path and the variation of the flow path resistance. Even if there is a situation, the reference voltage Vref also fluctuates accordingly, so that such fluctuation can be offset and the reliability of adsorption completion detection can be improved. Moreover, the reference voltage Vref is automatically set when the rate of change of the air pressure becomes equal to or lower than the predetermined value. Therefore, the operator is relieved from the delicate operation of setting and correcting the reference voltage, and the automatic operation is performed. And productivity is improved.

In the above embodiment, the reference voltage Vref is a value obtained by multiplying the pressure measurement voltage Vx at the time when the change rate of the air pressure is below a predetermined value by a predetermined multiplication factor, but the present invention is not limited to this. is not. For example, the reference voltage Vref may be a voltage obtained by adding a predetermined value to the pressure measurement voltage Vx at the time when the rate of change of the air pressure becomes a predetermined value or less, or the pressure measurement when a predetermined time has elapsed from that time. The voltage Vx may be used as the reference voltage Vref. In short, the reference value is set according to the value measured by the pressure sensor on condition that the pressure change rate detecting means detects that the pressure change rate is less than or equal to a predetermined value. It should be done.

Besides, the present invention is not limited to the embodiment described above and shown in the drawings. For example, as shown in FIG. 6, the pressure measurement voltage Vx is compared with the reference value by the comparator 38, and The pressure change rate detecting means 20 and the reference value setting means 10 may be operated after the pressure measurement voltage Vx reaches a certain level, and various changes may be made without departing from the scope of the invention. Can be done.

[0035]

[Effect of the device]

 As described above, according to the suction completion detecting device in the component suction device of the present invention, even if the air pressure indicated when the component is sucked by the suction nozzle fluctuates due to various factors, Since the reference value for the judgment changes according to the fluctuation, the fluctuation can be offset and the reliability of the adsorption completion detection can be greatly improved.

[Brief description of drawings]

FIG. 1 is a circuit diagram of essential parts showing an embodiment of the present invention.

[Figure 2] Voltage waveform diagram of each part

FIG. 3 is a graph showing changes in pressure measurement voltage Vx when a screw is adsorbed.

FIG. 4 Pressure measurement voltage V when adsorbed screws fall off
graph showing changes in x

FIG. 5 is a block diagram showing an outline of a component suction device.

FIG. 6 is a circuit diagram showing a circuit for starting the adsorption completion detecting device.

FIG. 7 is a pressure change characteristic diagram showing the detection principle of a conventional adsorption completion detecting device.

[Explanation of symbols]

In the drawing, 1 is an adsorption nozzle, 3 is an exhaust pump, 4 is a pressure sensor, 7 is a comparator, 10 is a reference value setting means, 14 is a hold circuit, 18 is a non-inverting amplifier, 20 is a pressure change rate detecting means, and 24a. , 24b are sample and hold circuits, 30 is a comparator, and 34 and 36 are D type flip-flops.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masaya Funabashi 3-5-3 Akebonocho, Tachikawa, Tokyo Sanx Co., Ltd. (72) Iksei Yamada 3-5-3 Akebonocho, Tachikawa, Tokyo Within S Corporation

Claims (1)

[Scope of utility model registration request] 1. A component suction device comprising a suction nozzle for sucking a suction target component and an exhaust pump for sucking air through the suction nozzle, wherein an exhaust path from the suction nozzle to the exhaust pump is provided. In a suction completion detecting device that measures the air pressure of a predetermined portion with a pressure sensor and compares the measured value with a predetermined reference value to detect the suction completion of the suctioned component on the suction nozzle, the pressure sensor measures the air pressure. The pressure change rate detecting means for detecting that the change rate of the air pressure is below a predetermined value, and the condition that the pressure change rate is below a predetermined value is detected by the pressure change rate detecting means. A suction completion detecting device in a component suction device, comprising: a reference value setting means for setting the reference value in accordance with a value measured by the pressure sensor.