JP5493933B2 - Vacuum pressure control device and vacuum pressure control method - Google Patents

Description

  The present invention relates to a vacuum pressure control device used to apply a negative pressure to, for example, a suction head that sucks parts, and a vacuum pressure control method using the vacuum pressure control device.

  2. Description of the Related Art Conventionally, a vacuum suction device has been used for applications in which various parts and members such as electronic parts are sucked and held. In particular, when the workpiece to be sucked is small or easily damaged, it is required to control the suction pressure generated by the vacuum suction device, that is, the negative pressure with high accuracy.

  For example, Patent Document 1 below discloses a vacuum chuck device shown in FIG. As shown in FIG. 5, the vacuum chuck device 101 has a vacuum source 102. A suction pad 104 is connected to the vacuum source 102 via a flow path 103. A suction hole 104 a is formed in the suction pad 104. A suction hole 104 a is connected to the flow path 103. The workpiece W is sucked by the suction pad 104 on the side opposite to the side to which the flow path 103 of the suction hole 104a is connected. A vacuum sensor 105 that is a pressure sensor is connected to the flow path 103. The degree of vacuum by the vacuum source 102, that is, the magnitude of the negative pressure is adjusted according to the value of the negative pressure measured by the vacuum sensor 105.

  On the other hand, Patent Document 1 also discloses a vacuum chuck device 111 shown in FIG. The vacuum chuck device 111 is provided with a vacuum sensor 105 for detecting the negative pressure in the flow path 103. In addition, a flow sensor 112 is provided in the flow path 103. In order to generate different negative pressures, the first and second pressure gauges 113 and 114 are connected in parallel in the middle of the flow path 103. An electromagnetic valve 115 is provided to switch between the first pressure gauge 113 and the second pressure gauge 114. In the vacuum chuck device 111, the control device 116 is connected to the vacuum sensor 105, the flow sensor 112, the electromagnetic valve 115, and the vacuum source 102.

  Here, when the negative pressure detected by the vacuum sensor 105 exceeds a predetermined threshold value and the gas flow rate detected by the flow rate sensor 112 falls below the predetermined threshold flow rate, control is performed so as to lower the negative pressure. Control is performed by the device 116. That is, the magnitude of the negative pressure is controlled by the control device 116 so that an appropriate negative pressure that does not cause destruction or damage of the workpiece W is applied.

JP 2006-130625 A

  In the vacuum chuck device 101 of Patent Document 1, the negative pressure supplied from the vacuum source 102 is controlled so that the negative pressure detected by the vacuum sensor 105 becomes a target negative pressure. However, although not described in detail in Patent Document 1, there is a problem that the vacuum pressure generated by the vacuum source 102 is not always stable. In general, in order to generate a negative pressure, a negative pressure generating device that connects a gas such as air to a subsequent stage of a vacuum suction device such as a vacuum pump to obtain a predetermined negative pressure is connected. However, it is difficult to control the amount of gas supplied to the negative pressure generator with high accuracy because the performance of the environment change and the performance of a throttle valve for introducing air is insufficient.

  In the vacuum chuck device 111 shown in FIG. 6, not only the vacuum sensor 105 but also the flow rate sensor 112 is used when controlling the negative pressure supplied from the vacuum source 102. However, as described above, the flow sensor 112 is provided to perform control so that the negative pressure supplied to the suction pad 104 does not increase, that is, the magnitude of the negative pressure becomes a certain level or less. It is what. Therefore, even in the vacuum chuck device 111, the negative pressure supplied from the vacuum source 102 that generates the negative pressure cannot be stabilized.

  An object of the present invention is to eliminate the above-mentioned disadvantages of the prior art and to control the negative pressure generated by the negative pressure generator to a target negative pressure with high accuracy and a vacuum pressure. It is to provide a control method.

The vacuum pressure control device according to the present invention is configured to supply a gas to the negative pressure generating device and the negative pressure generating device to change the negative pressure generated by the negative pressure generating device. A gas supply source connected to the negative pressure generator. A flow controller is connected between the negative pressure generator and the gas supply source. The flow rate controller changes the flow rate of the gas supplied to the negative pressure generator. The vacuum pressure control device according to the present invention detects a pressure sensor provided to measure the negative pressure generated by the negative pressure generator and a gas flow rate F actually supplied to the negative pressure generator. The flow rate sensor provided in the. Further, first and second control devices are provided. The first control device includes a pressure value P detected by the pressure sensor, and comparing the target negative pressure P _0, if different, to the relationship between the negative pressure and the gas flow rate obtained in advance Based on the target negative pressure P ₀ , the target gas flow rate F ₀ is calculated. The second control device compares the target gas flow rate F ₀ with the gas flow rate F detected by the flow rate sensor and actually supplied to the negative pressure generator, and F = F _0. As described above, the gas flow rate set by the flow rate controller is changed.

  In a specific aspect of the vacuum pressure control device according to the present invention, the flow rate sensor is integrated with the flow rate controller. Therefore, the gas flow rate set by the flow rate controller can be controlled with higher accuracy. In addition, the number of parts can be reduced.

A vacuum pressure control method according to the present invention is a vacuum pressure control method for controlling a negative pressure generated by a negative pressure generating device, the step of detecting the negative pressure generated by the negative pressure generating device, and a detection the pressure value P of the negative pressure which is, compared to the value of the target negative pressure P ₀ which is stored in advance, and the detected pressure value P, if the target negative pressure P ₀ are different, previously determined Calculating the target gas flow rate F ₀ based on the relationship between the negative pressure and the supply gas flow rate by the flow rate controller connected to the negative pressure generator, and the gas by the flow rate controller so as to be the target gas flow rate F _0. A step of setting a flow rate, a step of detecting a gas flow rate F currently supplied to the negative pressure generator, the target gas flow rate F _0, and a gas flow rate F actually supplied detected by the flow rate sensor, And F = As becomes ₀ and a step of changing the gas flow rate by the flow controller.

  According to the vacuum pressure control device and the vacuum pressure control method of the present invention, not only the pressure value detected by the pressure sensor and generated by the negative pressure generator, but also supplied to the negative pressure generator. Since the gas flow rate to be supplied to the negative pressure generator is controlled based on the gas flow rate F, the value of the negative pressure generated in the negative pressure generator, that is, the degree of vacuum is controlled with high accuracy. Can do. Therefore, a target negative pressure can be reliably applied to a device using negative pressure such as a suction pad connected to the negative pressure generator.

It is a schematic block diagram of the vacuum pressure control apparatus which concerns on one Embodiment of this invention. It is a schematic block diagram of the negative pressure generator used by one Embodiment of this invention. It is a schematic block diagram which shows an example of the controller with which the flow sensor was integrated. It is a flowchart for demonstrating the vacuum pressure control method of one Embodiment of this invention. It is a schematic block diagram which shows an example of the conventional vacuum chuck apparatus. It is a schematic block diagram which shows the other example of the conventional vacuum chuck apparatus.

  Hereinafter, the present invention will be clarified by describing specific embodiments of the present invention with reference to the drawings.

  FIG. 1 is a schematic configuration diagram of a vacuum pressure control apparatus according to an embodiment of the present invention.

  The vacuum pressure control device 1 has a negative pressure generator 2. The negative pressure generator 2 is connected to a gas supply source 8 via a flow path 6. The gas supply source 8 is configured by an appropriate compressed gas supply device that supplies compressed air such as a compressor. A flow rate controller 9 is connected in the middle of the flow path 6. The flow rate controller 9 changes the flow rate of the compressed air supplied from the gas supply source 8.

  The structure of the negative pressure generator 2 will be described with reference to the schematic configuration diagram of FIG. The negative pressure generator 2 is an ejector-type negative pressure generator that generates a negative pressure using compressed air. As shown in FIG. 2, the negative pressure generator 2 has a supply port 2a to which compressed air is supplied. The supply port 2a is connected to the flow path 6 shown in FIG. A nozzle 3 is provided in the negative pressure generator 2. The nozzle 3 is connected to the supply port 2a. Therefore, the compressed air is supplied to the nozzle 3 whose tip diameter is reduced. The tip of the nozzle 3 is located in a diffusion chamber 2 d provided in the negative pressure generator 2. The compressed air flow squeezed by the nozzle 3 is discharged into the diffusion chamber 2d and expands in the diffusion chamber 2d. A flow path 2e and a diffuser 2f are connected to the diffusion chamber 2d. The diffuser 2f is located in front of the nozzle 3 and is connected to the exhaust port 2c. On the other hand, the flow path 2e has a tip connected to the diffusion chamber 2d and the other end connected to the port 2b. The flow path 7 of FIG. 1 is connected to the port 2b.

  The compressed air expanded in the diffusion chamber flows into the diffuser 2f at a high speed. Due to this high-speed air flow, the pressure in the diffusion chamber 2d is reduced and negative pressure is generated. This negative pressure is applied to the flow path 7. That is, the flow path 7 is maintained at a negative pressure.

  Returning to FIG. 1, a flow rate controller 9 is provided in the middle of the flow path 6. The flow controller 9 can be formed by an appropriate gas flow variable device such as a throttle valve. The flow rate controller 9 can adjust the flow rate of the gas supplied from the gas supply source 8 to the flow path 6. Thereby, the flow rate of gas such as compressed air supplied to the negative pressure generator 2 can be changed. By changing the gas flow rate, the value of the negative pressure generated by the negative pressure generator 2 can be adjusted.

  On the other hand, in the present embodiment, in order to detect the negative pressure generated by the negative pressure generator 2, more specifically, the pressure sensor 10 is provided to detect the pressure in the flow path 7. The pressure sensor 10 can be configured by an appropriate pressure detection device such as a differential pressure type, for example.

  In addition, a flow sensor 11 is provided to detect the gas flow rate supplied to the negative pressure generator 2. The flow sensor 11 detects the flow rate of the gas flowing through the flow path 6, that is, the flow rate of the gas supplied to the negative pressure generator 2. The flow sensor 11 can be configured by an appropriate gas flow rate detection device such as a hot wire type, for example.

  The vacuum pressure control device 1 includes a first control device 13 and a second control device 14. The first control device 13 is connected to the pressure sensor 10. A pressure value detected by the pressure sensor 10 is given to the first control device 13.

  In the first control device 13, the target negative pressure P generated by the negative pressure generator 2 is input from an external input means (not shown) and stored in advance. Further, the first control device 13 stores a relational expression between a negative pressure generated in the negative pressure generating device 2 set in advance and a gas flow rate supplied to the negative pressure generating device 2. When the pressure value detected by the pressure sensor 10 is different from the target negative pressure, the first control device 13 calculates the target gas flow rate F corresponding to the target negative pressure based on the above relational expression.

  The second control device 14 is connected to the first control device 13. The target gas flow rate F calculated by the first controller 13 is given to the second controller 14.

  The flow rate sensor 11 is connected to the second control device 14. The gas flow rate F measured by the flow sensor 11, that is, the gas flow rate F currently supplied to the negative pressure generator 2 is supplied to the second controller 14.

  The second control device 14 is connected to the flow rate controller 9. The second control device 14 controls the gas flow rate set by the flow rate controller 9. Preferably, as shown by the solid line A in FIG. 3, the flow sensor 11 is integrated with the flow controller 9.

  In the structure in which the flow rate sensor 11 is integrated with the flow rate controller 9, the gas flow rate actually sent out set by the flow rate controller 9 can be detected and controlled with high accuracy. In addition, the number of parts can be reduced. However, the flow sensor 11 is not necessarily integrated with the flow controller 9. That is, as long as the gas flow rate actually supplied to the negative pressure generator 2 can be measured, the flow rate sensor 11 may be configured separately from the flow rate controller 9.

  Further, the flow rate sensor 11 and the flow rate controller 9 and the second control device 14 may be integrated.

  Note that the vacuum pressure control device 1 of the present embodiment is used to apply a negative pressure to the suction pad 15 connected to the flow path 7 and hold W by suction. For the suction pad 15, an appropriate structure capable of sucking the workpiece W by conventional vacuum suction can be used.

  Next, a vacuum pressure control method according to an embodiment of the present invention will be described with reference to the flowchart of FIG.

First, gas is supplied from the gas supply source 8 from the initial state, and the negative pressure is generated by the negative pressure generator 2. The generated negative pressure is detected by the pressure sensor 10 in step S51. The pressure value detected by the pressure sensor 10 is given to the first control device 13. The pressure value is compared with the target negative pressure that has been input in advance. In step S52, the first controller, the measured pressure value is compared with the target negative pressure P _0, it is determined whether equal. When the pressure value P is equal to the target negative pressure P ₀ ends the control.

If P is different from P ₀ , in step S53, a target gas flow rate F ₀ that is a target negative pressure is calculated based on the above relational expression.

Next, in step S54, the target gas flow rate F ₀ which is calculated in the first control unit 13 is applied to the second control unit 14, as the second control unit 14, the target gas flow rate F ₀ The flow controller 9 is controlled. That is, to change the flow rate in the flow controller 9 so that the target gas flow rate F _0.

  In step S55, the flow rate sensor 11 detects the gas flow rate F currently supplied to the negative pressure generator 2.

In step S56, the second controller 14, and the gas flow rate F of gas currently being supplied given from the flow sensor 11 is compared with the above-mentioned target gas flow rate F _0. Then, if it is F = F _0, since the target gas flow rate F ₀ is realized, the control is ended. In this case, since the target gas flow rate F ₀ is realized, the target negative pressure P ₀ is reliably set in the negative pressure generating device, and the negative pressure of the flow path 7 and hence the adsorption connected to the flow path 7 is achieved. The suction force in the pad 15 can be a target pressure. Therefore, the work W can be reliably sucked and held by the suction pad 15.

On the other hand, in step S56, if F is not equal to _{F 0,} in step S57, the second controller 14 changes the gas flow. This change in gas flow rate, F is the gas flow rate is changed in the flow controller 9 such that the F _0. Thereafter, the process returns to step S51, and steps S53, S54, S55, and S56 are repeated again. Therefore, according to the vacuum pressure control method of this embodiment, the gas flow rate supplied to the negative pressure generating device 2 can be reliably targeted gas flow F _0. Therefore, it is possible to reliably target negative pressure P ₀ the negative pressure generated by the vacuum generator 2.

  In the conventional vacuum chuck devices 101 and 111, no consideration has been given to the generated negative pressure of the vacuum source 102 corresponding to the portion up to the negative pressure generator 2 in the vacuum pressure control device of the present invention. As described above, in practice, the generated negative pressure tends to vary because it is affected by environmental changes and the performance of the diaphragm source used in the negative pressure generator. Therefore, in the conventional vacuum chuck devices 101 and 111, it is difficult to make the negative pressure applied to the final suction pad constant.

  On the other hand, according to the vacuum pressure control device 1 and the vacuum pressure control method of the present embodiment, the negative pressure set by the negative pressure generator 2 can be reliably set to the target pressure value. Therefore, the target negative pressure can be reliably applied to the suction pad 15 regardless of changes in the environment and regardless of variations in the performance of the members constituting the flow controller 9 and the negative pressure generator 2.

DESCRIPTION OF SYMBOLS 1 ... Vacuum pressure control apparatus 2 ... Negative pressure generator 2a ... Supply port 2b ... Port 2c ... Exhaust port 2d ... Diffusion chamber 2e ... Channel 2f ... Diffuser 3 ... Nozzle 6 ... Channel 7 ... Channel 8 ... Gas supply source DESCRIPTION OF SYMBOLS 9 ... Flow controller 10 ... Pressure sensor 11 ... Flow sensor 13 ... 1st control apparatus 14 ... 2nd control apparatus 15 ... Pad for adsorption | suction

Claims (3)

A negative pressure generator for generating negative pressure;
A gas supply source connected to the negative pressure generator so as to supply gas to the negative pressure generator in order to change the negative pressure generated by the negative pressure generator;
A flow rate controller that is connected between the negative pressure generator and the gas supply source, and that changes a flow rate of gas supplied to the negative pressure generator;
A pressure sensor provided to measure the negative pressure generated by the negative pressure generator;
A flow sensor provided to detect the flow rate of the gas actually supplied to the negative pressure generator;
The pressure value P detected by the pressure sensor is compared with the value of the target negative pressure P ₀ stored in advance. When the detected pressure value P is different from the target negative pressure P ₀ , it is obtained in advance. A first controller that calculates a target gas flow rate F ₀ corresponding to the target negative pressure P ₀ based on the relationship between the negative pressure and the gas flow rate;
The gas flow F currently detected by the flow sensor and supplied to the negative pressure generator is compared with the target gas flow F ₀ obtained by the first controller, and F ₀ is different from F. A vacuum pressure control device comprising: a second control device that changes the gas flow rate set by the flow rate controller to F = F ₀ .   The vacuum pressure control device according to claim 1, wherein the flow sensor is provided integrally with the flow controller. A vacuum pressure control method for controlling the negative pressure generated by the negative pressure generator,
Detecting a negative pressure generated by the negative pressure generator;
The detected pressure value P of the negative pressure is compared with the previously stored target negative pressure P ₀ value. If the detected pressure value P and the target negative pressure P ₀ are different, it is obtained in advance. Calculating a target gas flow rate F ₀ based on the relationship between the negative pressure and the supply gas flow rate by the flow rate controller connected to the negative pressure generator;
Setting a gas flow rate by a flow rate controller to be the target gas flow rate F ₀ ;
Detecting a gas flow rate F currently supplied to the negative pressure generator;
A step of comparing the target gas flow rate F ₀ with the gas flow rate F that is actually supplied detected by the flow rate sensor, and changing the gas flow rate by the flow rate controller so that F = F _0. Control method.

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