JP6921374B2 - Vacuum valve - Google Patents

Description

The present invention relates to a vacuum valve.

In a vacuum processing apparatus such as a CVD apparatus, the pressure in the chamber usually differs depending on the stage of the processing process (for example, during or before and after the process). Therefore, in such a vacuum processing apparatus, a valve having variable conductance is provided between the vacuum chamber and the vacuum pump to adjust the pressure. As an example of such a valve, the one described in Patent Document 1 is known.

Japanese Unexamined Patent Publication No. 2011-137537

The motor that drives the valve body PWM drives the applied voltage by switching switching elements such as FETs, and controls the motor so that a sinusoidal current flows through the motor. By the way, when the valve body is driven at high speed, the voltage of the DC power supply line of the switching circuit may rise above the supply voltage due to the counter electromotive force when the drive current of the motor decreases when the valve body is stopped. Due to this voltage rise, a voltage exceeding the rated voltage is applied to the circuit components connected to the DC power supply line, which causes component failure.

Vacuum valve according to a preferred embodiment of the present invention includes a valve body, a motor for driving the valve body, a switching circuit for turning on and off the application of the DC voltage to the winding of the motor is inputted to the switching circuit DC The voltage input line includes an on-off circuit provided in parallel with the switching circuit and capable of conducting and interrupting current, and the on-off circuit is used for the switching during on / off operation of the switching circuit in the deceleration drive of the motor. It is in a conductive state when the circuit is turned on.
In a further preferred embodiment, the on-off circuit is a circuit connected in series to the switching element resistance and the switching element, the deceleration driving of the motor is turned on a timing at the on-state of the switching circuit.
In a more preferred embodiment, the voltage detection unit for detecting the voltage of the input line is further provided, and the switching circuit is described when the detection voltage of the voltage detection unit is equal to or higher than a predetermined threshold value during deceleration drive of the motor. It is in a conductive state when the switching circuit is turned on.

According to the present invention, it is possible to prevent the voltage rise of the DC power supply line during the deceleration operation.

FIG. 1 is a diagram showing the appearance of a vacuum valve. FIG. 2 is a block diagram showing details of the valve drive unit and the valve control unit. FIG. 3 is a block diagram showing details of the valve body driving unit. FIG. 4 is a diagram illustrating a voltage applied to the winding of the motor and a current flowing through the winding. FIG. 5 is a diagram illustrating the generation of overvoltage.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing the appearance of the vacuum valve 1 according to the present embodiment. 1 (a) is a plan view, and FIG. 1 (b) is a side view. The vacuum valve 1 includes a valve body 2 provided with a valve plate 6, a valve drive unit 3 for opening and closing the valve plate 6, and a valve control unit 4 for controlling the valve drive unit 3.

A valve opening 50 is formed in the valve housing 5 of the valve body 2. An intake flange 51 is provided on the intake side of the valve opening 50, that is, on the upper surface side of the valve housing 5 shown in the drawing. On the other hand, an exhaust port flange (not shown) is provided on the exhaust side of the valve opening 50, that is, on the back side of the valve housing 5 (not shown).

The valve plate 6 is oscillated as shown by a broken line arrow by a motor 31 provided in the valve drive unit 3. When the valve plate 6 is oscillated by the motor 31, the valve plate 6 slides in the horizontal direction to open and close the valve. The valve plate 6 can be slid to an arbitrary position between the position A0 having an opening degree of 0% facing the entire valve opening 50 and the position A1 having an opening degree of 100% when the valve opening 50 is fully opened. can. When the valve plate 6 is driven to the position A0 and the valve opening 50 is further sealed by the valve plate 6, a sealing member (not shown) is pressed against the valve plate 6 to seal the valve plate 6. The seal member is driven by compressed air.

FIG. 2 is a block diagram of a valve drive unit 3 and a valve control unit 4 of the vacuum valve 1. The valve drive unit 3 is provided with a motor 31 for opening and closing the valve plate 6 (see FIG. 1). The drive position of the valve plate 6 is detected by the position detector 32. As the position detector 32, for example, an encoder that detects the amount of rotation of the motor 31 is used. The position of the valve plate 6 can be obtained from the amount of rotation of the motor 31.

The valve control unit 4 is connected to an external DC power supply and an upper controller 100 via an external interface 42. The vacuum valve 1 is supplied with electric power from an external DC power source. As the DC power supply, for example, a DC 24V power supply is used. The host controller 100 is a controller of a vacuum device to which the vacuum valve 1 is mounted. The opening / closing operation of the vacuum valve 1 is performed by a command from the host controller 100. The command from the host controller 100 is input to the main control unit 41 via the communication unit 43.

The DC power from the DC power supply is input to the DC-DC converter 44, the valve body drive unit 45, the pressure sensor 33, and the like. The pressure sensor 33 is a sensor that detects the pressure of the compressed air that drives the seal member described above. The DC power input from the DC power supply to the valve body drive unit 45 is used as the drive power for the motor 31. The DC power input to the DC-DC converter 44 is converted into lower voltage DC power by the DC-DC converter 44 and supplied to each unit including the main control unit 41.

The main control unit 41 outputs a drive control signal based on the input command to the valve body drive unit 45. The valve body drive unit 45 drives the motor 31 based on the drive control signal from the main control unit 41. The display unit 47 displays the state and settings of the vacuum valve 1. For maintenance and the like, various commands can be input to the main control unit 41 by manually operating the operation unit 46 provided in the valve control unit 4.

Next, FIG. 3 is a block diagram showing details of the valve body driving unit 45. Here, the case where the motor 31 is a two-phase motor will be described as an example. The motor 31 includes a rotor 311 and an A-phase winding 312A and a B-phase winding 312B. The valve body drive unit 45 includes a switching circuit 451A that controls the on / off of the DC voltage Vdc applied to the A-phase winding 312A, and a switching circuit 451B that controls the on / off of the DC voltage Vdc applied to the B-phase winding 312B. A switching element SW0, a resistor R, and a motor control unit 452 are provided.

The switching circuit 451A includes an H-bridge circuit including four switching elements SW1 to SW4. The switching circuit 451B also includes an H-bridge circuit similar to the switching circuit 451A. The switching element SW0 and the resistor R are connected in series, and the series connection circuit is connected in parallel to the DC voltage input lines of the switching circuits 451A and 451B, respectively. The motor control unit 452 outputs an on / off control signal to each of the switching elements SW0 and the switching elements SW1 to SW4 of the switching circuits 451A and 451B. For the switching elements SW0 and SW1 to SW4, for example, FETs and the like are used.

In the case of a two-phase motor, as shown in FIG. 4, the rotation is controlled by shifting the current phase between the A phase and the B phase by 90 °. 4A and 4B are diagrams for explaining the voltage applied to the windings 312A and 312B and the current flowing through the windings 312A and 312B. FIG. 4A shows the case of the A phase, and FIG. 4B shows the case of the B phase. Is shown. In FIGS. 4 (a) and 4 (b), the upper row shows the voltage and the lower row shows the current. In the A phase of FIG. 4A, the switching elements SW1 and SW4 are turned on, the current Icw that rotates the rotor 311 clockwise (CW direction) flows, and the switching elements SW2 and SW2 are reversed at the timing when the magnetic poles of the rotor 311 are reversed. By turning on SW3 and passing a current (−Icw), the rotation of the rotor 311 in the CW direction is continued. In the case of the B phase of FIG. 4B, the switching elements SW1 and SW4 and the switching elements SW2 and SW3 are turned on in order at a timing shifted (advanced) by 90 °. By changing the on-duty of the pulse of the applied voltage in a sinusoidal manner by PWM control, a sinusoidal current flows in each of the phases A and B.

At the time of deceleration, the on-duty is gradually reduced, and further, by turning on the switching elements SW2 and SW3 during the period when the switching elements SW1 and SW4 in FIG. 4 are turned on, the current Iccw in the reverse direction is passed and the motor brake is applied. However, when the valve plate 6 is stopped rapidly, as shown in FIG. 5, the current I2 due to the counter electromotive force becomes larger than the current I1 due to the application of the DC voltage Vdc, and the net current I3 is opposite to the current I. It may be oriented. At this time, a phenomenon occurs in which the voltage of the DC line rises above the supplied DC voltage Vdc as shown by the hatching in FIG. 5 due to the reverse current I3 flowing.

Therefore, in the present embodiment, as shown in FIG. 3, a series connection circuit of the switching element SW0 and the resistor R is provided in parallel with the switching circuits 451A and 451B in each of the input side DC lines of the switching circuits 451A and 451B. rice field. Then, at the time of deceleration control, the switching element SW0 is turned on in synchronization with the on timing of the switching elements SW1 and SW4 or the switching elements SW2 and SW3 that are performing the on control.

Consider a case where a rapid deceleration operation is performed as described above and a reverse current flows due to a counter electromotive force as shown in Icw_b in FIG. At this time, by turning on the switching element SW0, the current Icw_b flows to GND via the switching element SW0 and the resistor R, so that the voltage rise of the DC line can be prevented. As a result, it is possible to prevent an overvoltage from being applied to a device (for example, the pressure sensor 33) to which the DC voltage Vdc is supplied, and it is possible to prevent a failure or the like due to the overvoltage.

(1) As described above, the vacuum valve 1 is a switching circuit 451A that turns on and off the application of the DC voltage Vdc to the valve plate 6, the motor 31 that drives the valve plate 6, and the windings 312A and 312B of the motor 31. , 451B and the switching circuit (switching element SW0 and resistor R) provided in parallel with the switching circuits 451A and 451B on the input line of the DC voltage Vdc input to the switching circuits 451A and 451B and capable of conducting and interrupting the current. The series connection circuit is brought into a conductive state in synchronization with the on-timing of the switching circuits 451A and 451B when the motor 31 is decelerated and driven. As a result, at the on-timing, the current I3 (Icw_b) in the direction opposite to the rotation drive current I1 generated as a result of the generation of the counter electromotive force flows to GND via the switching circuit, and the voltage of the input line is maintained at Vcd. ..

(2) In the above-described embodiment, a series connection circuit of the switching element SW0 and the resistor R is provided as an switching circuit capable of conducting and interrupting the current, but the switching circuit is not limited to this configuration.

(3) Further, as shown by the broken line in FIG. 3, a voltage sensor 200 for detecting the voltage of the input line is provided, and the switching element SW0 is decelerated and driven, and the detection voltage of the voltage sensor 200 is a predetermined threshold value. When (Vdc + ΔV) or more, the above-mentioned opening / closing circuit may be brought into a conductive state in synchronization with the on-timing of the switching circuits 451A and 451B. ΔV is a determination value for determining whether or not the voltage of the input line is an overvoltage. Therefore, it is possible to prevent the voltage of the input line from exceeding a predetermined threshold value (Vdc + ΔV).

Although various embodiments and modifications have been described above, the present invention is not limited to these contents. Other aspects conceivable within the scope of the technical idea of the present invention are also included within the scope of the present invention.

1 ... Vacuum valve, 2 ... Valve body, 3 ... Valve drive unit, 4 ... Valve control unit, 6 ... Valve plate, 31 ... Motor, 41 ... Main control unit, 44 ... DC-DC converter, 45 ... Valve body drive unit , 451A, 451B ... Switching circuit, 452 ... Motor control unit, SW0 to SW2 ... Switching element

Claims (3)

With the valve body,
The motor that drives the valve body and
A switching circuit that turns on and off the application of DC voltage to the windings of the motor,
The DC voltage input line input to the switching circuit is provided with an on-off circuit provided in parallel with the switching circuit and capable of conducting and interrupting current.
The opening / closing circuit is a vacuum valve that is brought into a conductive state at the on-timing of the switching circuit during the on / off operation of the switching circuit in the deceleration drive of the motor. In the vacuum valve according to claim 1,
The switching circuit is a circuit in which a switching element and a resistor are connected in series.
The switching element is a vacuum valve that is turned on when the switching circuit is turned on when the motor is decelerated. In the vacuum valve according to claim 1,
A voltage detector for detecting the voltage of the input line is further provided.
The opening / closing circuit is a vacuum valve that is brought into a conductive state at the on-timing of the switching circuit when the detection voltage of the voltage detection unit is equal to or higher than a predetermined threshold value during deceleration drive of the motor.

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