JP2018145803A - Control device, circuit board installed at said control device and vacuum pump applied with said control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device having a simple heat radiation structure enabling a cost at the time of replacement of its component element to be reduced in which a smaller type pump than that of the prior art can be constituted and its manufacturing can be carried more easily, a circuit board installed at said control device and a vacuum pump applied with said control device.SOLUTION: A driving current amplifier 5 including FET for use in flowing electric current against an electro-magnet 104 of a magnet bearing or the like and a driving current amplifier 7 including FET for use in flowing electric current against a three-phase motor 121 are installed on one power substrate 21. In turn, a magnet bearing floating control 6 composed of light current elements including a digital circuit or a sensor circuit for use in controlling floating of the magnetic bearing and light current elements including a digital circuit or a sensor circuit requisite for a rotating speed control 8 against the motor 121 are installed on one control board 23. Since only power substrate 21 includes the power element, only this power substrate 21 has a short life due to heat and it is easily troubled in operation. The power substrate 21 is fixed against a frame 12 through a heat radiation sheet 24.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a control device, a board mounted on the control device, and a vacuum pump to which the control device is applied. In particular, the heat dissipation structure is simple, and the cost for replacing parts can be reduced. The present invention relates to a control device that can be configured easily, and is easy to manufacture, a substrate mounted on the control device, and a vacuum pump to which the control device is applied.

With the recent development of electronics, the demand for semiconductors such as memories and integrated circuits is increasing rapidly.
These semiconductors are manufactured by doping impurities into a highly pure semiconductor substrate to impart electrical properties, or by forming fine circuits on the semiconductor substrate by etching.

  These operations need to be performed in a high vacuum chamber in order to avoid the influence of dust in the air. A vacuum pump is generally used for evacuating the chamber. However, a turbo molecular pump, which is one of the vacuum pumps, is used frequently from the viewpoints of particularly low residual gas and easy maintenance.

Also, in the semiconductor manufacturing process, there are many processes in which various process gases are applied to the semiconductor substrate. The turbo molecular pump not only evacuates the chamber, but also exhausts these process gases from the chamber. Also used.
Furthermore, turbo molecular pumps are also used in equipment such as electron microscopes to prevent the refraction of the electron beam due to the presence of dust, etc., so that the environment in the chamber of the electron microscope or the like is brought into a highly vacuum state. Yes.

The turbo molecular pump includes a pump body and a control device that controls the pump body.
The pump body and the control device are usually connected by a cable and a connector plug mechanism. Moreover, in order to avoid the cable connection mistake between this pump main body and a control apparatus, and the complexity of cable length adjustment, the structure which integrated the pump main body and the control apparatus like the prior art document 1 is known. .

An internal block diagram of this control device is shown in FIG.
As shown in FIG. 4, conventionally, there is one drive current amplifier 5 and one magnetic bearing levitation control 6 for each electromagnet of an active magnetic bearing (hereinafter referred to as AMB) mainly because of functional separation and ease of design. On the other hand, the drive current amplifier 7 and the rotational speed control 8 for the motor were carried by a single motor board 2. The AMB board 1 and the motor board 2 transmit a signal to the user 4 or receive a command signal from the user via one interface board 3 including the user interface 9 and the I / O port 11. It was.

  Here, on the AMB substrate 1, a power amplifying element including an FET and the like necessary for amplifying a driving current for each electromagnet and a weak electric element including a digital circuit and a sensor circuit for magnetic bearing levitation control were mounted on the same substrate. . The motor board 2 is mounted on the same board with a power amplifying element including an FET and the like necessary for driving current amplification for a three-phase motor and a weak electric element including a digital circuit and a sensor circuit for controlling the rotation of the motor. It was.

JP 2007-32535 A

  However, when the circuit is separated from the functional surface as described above, since the drive current amplification elements exist on both the AMB substrate 1 and the motor substrate 2, the amount of heat generated by the elements on the respective substrates is large. It was necessary to take measures against heat radiation for both the substrate 1 and the motor substrate 2. For this reason, on the AMB substrate 1 and the motor substrate 2, as shown in the board layout diagrams of FIGS. 4 and 5, a heat radiation sheet 13 that contacts the housing 12 and a heat radiation sheet 15 that contacts the housing lid 14 are disposed. Space was needed.

  When the case lid 14 is closed, the person cannot visually check the internal situation, so that the elements do not collide with each other as shown by the dotted lines in FIG. Therefore, it was arranged with a margin so as not to protrude in the height direction. This point requires a further margin in the height direction because the interface substrate 3 is also present. Therefore, the casing of the control device has to be large. Further, when closing the housing lid 14, since a person cannot visually confirm the internal situation, play is required for the inter-board cable during assembly work.

  In addition, since both the AMB substrate 1 and the motor substrate 2 generate heat in this way, both the AMB substrate 1 and the motor substrate 2 are likely to fail. Since there are many cases of replacement in units of substrates in the event of a failure, it is necessary to always keep a certain quantity of both the AMB substrate 1 and the motor substrate 2 for replacement.

  Further, each of the AMB board 1 and the motor board 2 includes a drive current amplification element and a digital circuit or a low-power circuit of a sensor circuit on one board. In order to prevent noise from getting on the low-power circuit side, it is necessary to divide the areas of the power-related elements and the weak-power-related elements, and the substrate becomes larger accordingly.

  Furthermore, since the AMB substrate 1 and the motor substrate 2 are equipped with amplification elements such as FETs, it is necessary to widen the wiring pattern width in accordance with the amount of current. In addition, due to the wide copper foil, the gap between the elements is increased, and the AMB substrate 1 and the motor substrate 2 are increased.

  The present invention has been made in view of such a conventional problem, the heat dissipation structure is simple, the cost at the time of component replacement can be reduced, and a control device that can be configured as a smaller pump than ever, and is easy to manufacture, It is an object of the present invention to provide a substrate mounted on the control device and a vacuum pump to which the control device is applied.

  For this reason, the present invention (Claim 1) is an invention of a control device, comprising a power board on which a driving current amplifier for a magnetic bearing for passing a current to a magnetic bearing and a driving current amplifier for a motor for flowing a current to a motor are mounted; A control board responsible for levitation control by magnetic bearings and rotation speed control of the motor, and a housing for housing the control board and the power board are provided.

  Conventionally, the drive control for the magnetic bearing and the motor is divided into two types of substrates, that is, a substrate that requires electric power and a substrate that requires light electricity, compared to the case where the substrate is finely separated from the functional aspect. For this reason, the number of substrates to be accommodated is smaller than in the prior art, and the design can be reduced. In addition, the number of connectors crossing between the boards is reduced, so that the size can be reduced.

  Only the power board needs to dissipate heat, and only one heat dissipating sheet is sufficient. Only the power board has a short life due to heat and is prone to failure. Therefore, only one type of power board is prepared for replacement. Since only one type of substrate needs to be mass-produced, repair costs can be reduced. Since the control board generates a small amount of heat and is not affected by heat, the board has a long life and hardly breaks down. Natural air cooling is sufficient.

  Conventionally, the layout is complicated because it is necessary to arrange the substrate in the control device in consideration of heat dissipation. However, in the present invention, the heat dissipation can be concentrated and the layout is simple and the workability is improved. The board can be easily attached and the length of the cable can be minimized.

  In addition, the present invention (Claim 2) is an invention of a control device, wherein the control board further includes a user interface for monitoring and controlling the status of the magnetic bearing and the motor, and communication between the user and the user interface. The transmission part which performs is characterized by the above-mentioned.

  Furthermore, the present invention (Claim 3) is an invention of a control device, characterized in that a heat dissipation means is interposed between the power board and the housing.

  The heat dissipation means includes a heat sink and a heat dissipation sheet. Since there is only one place to install the heat dissipation means, the heat dissipation can be concentrated and the layout is simple and the workability is improved.

  Further, the present invention (Claim 4) is an invention of a control device, wherein the height of at least one electronic element mounted on the control board is within a maximum height range among the electronic elements mounted on the power board. A part or all of this is included.

  The layout can be designed so that the components between the boards do not interfere. Therefore, the height of the control device can be kept low. As a result, the height of the conventional control device can be kept low together with the fact that the number of substrates, which is the effect of claim 1, can be reduced.

  Furthermore, the present invention (Claim 5) is an invention of a control device, wherein the control board is supported inside the casing via a positioning means.

  The control board is supported by positioning means such as a rod erected from the housing, for example. For this reason, it is possible to perform the work of attaching the board or the connector while the operator confirms with the eyes with the housing lid opened. The assembly is one way. Therefore, attachment work is easy and the length of the cable can be minimized.

  Further, the present invention (invention 6) is an invention of a control device, wherein the thickness of the copper foil forming the wiring pattern of the power substrate is 35 μm or more.

  About a power board, a power element can be mounted more densely than before by narrowing the width | variety of the copper foil of a wiring pattern, and thickening the thickness of copper foil.

  Furthermore, the present invention (Claim 7) is an invention of a control device, wherein an electric current of 200 mA or more is passed through the electronic element mounted on the power board, while the electronic element mounted on the control board is A current of less than 200 mA is passed.

  Furthermore, the present invention (invention 8) is an invention of a power board, which is mounted on the control device according to any one of claims 1 to 7 and includes a power element.

  Furthermore, the present invention (Claim 9) is an invention of a control board, which is mounted on the control device according to any one of Claims 1 to 7, and includes a control including at least one of a digital circuit and a sensor circuit. It is characterized by having a weak electric element of the system.

  Furthermore, the present invention (Claim 10) is an invention of a vacuum pump, and is characterized in that the control device according to any one of Claims 1 to 7 is applied.

As described above, according to the present invention (Claim 1), a power board mounted with a magnetic bearing drive current amplifier for supplying current to a magnetic bearing and a motor drive current amplifier for supplying current to a motor, and a magnetic bearing Since the control board for controlling the flying height control and the rotation speed of the motor is separated, the number of boards to be accommodated can be reduced as compared with the prior art, and the design can be reduced. Only the power board needs to dissipate heat, and only one heat dissipating sheet is sufficient. Only the power board has a short life due to heat and is prone to failure. Therefore, only one type of power board is prepared for replacement.
Conventionally, the layout is complicated because it is necessary to arrange the substrate in the control device in consideration of heat dissipation. However, in the present invention, the heat dissipation can be concentrated and the layout is simple and the workability is improved.

Overall configuration diagram of an embodiment of the present invention The figure which showed the internal block of a control device with a substrate composition The figure which shows arrangement | positioning of the board | substrate inside a control apparatus. Figure showing the internal block of the control device together with the board configuration (conventional) Diagram showing the layout of the board inside the control device (conventional)

  Hereinafter, embodiments of the present invention will be described. FIG. 1 shows a configuration diagram of an embodiment of the present invention. In FIG. 1, a turbo molecular pump 10 includes a pump body 100 and a control device 200 that are integrated. However, even if the pump main body 100 and the control device 200 are separated, the present embodiment can be applied.

  An intake port 101 is formed at the upper end of the cylindrical outer cylinder 127 of the pump body 100. On the inner side of the outer cylinder 127, there is provided a rotating body 103 in which a plurality of rotating blades 102a, 102b, 102c,... By turbine blades for sucking and exhausting gas are formed radially and in multiple stages.

  A rotor shaft 113 is attached to the center of the rotating body 103, and the rotor shaft 113 is levitated and supported in the air by a so-called 5-axis control magnetic bearing.

  In the upper radial electromagnet 104, four electromagnets are arranged in pairs with an X axis and a Y axis that are radial coordinate axes of the rotor shaft 113 and are orthogonal to each other. An upper radial sensor 107 composed of four electromagnets is provided adjacent to and corresponding to the upper radial electromagnet 104. The upper radial sensor 107 is configured to detect a radial displacement of the rotating body 103 and send it to the control device 200.

  In the control device 200, excitation of the upper radial electromagnet 104 is controlled through a compensation circuit having a PID adjustment function based on the displacement signal detected by the upper radial sensor 107, and the upper radial position of the rotor shaft 113 is determined. adjust.

  The rotor shaft 113 is formed of a high permeability material (such as iron) and is attracted by the magnetic force of the upper radial electromagnet 104. Such adjustment is performed independently in the X-axis direction and the Y-axis direction.

  Further, the lower radial electromagnet 105 and the lower radial sensor 108 are arranged in the same manner as the upper radial electromagnet 104 and the upper radial sensor 107, and the lower radial position of the rotor shaft 113 is set to the upper radial position. It is adjusted in the same way.

  Furthermore, axial electromagnets 106A and 106B are arranged with a disk-shaped metal disk 111 provided at the lower part of the rotor shaft 113 sandwiched vertically. The metal disk 111 is made of a high permeability material such as iron. An axial sensor 109 is provided to detect the axial displacement of the rotor shaft 113, and the axial displacement signal is sent to the control device 200.

  The axial electromagnets 106A and 106B are excited and controlled through a compensation circuit having a PID adjustment function of the control device 200 based on the axial displacement signal. The axial electromagnet 106A and the axial electromagnet 106B attract the metal disk 111 upward and downward by magnetic force.

  As described above, the control device 200 appropriately adjusts the magnetic force exerted on the metal disk 111 by the axial electromagnets 106A and 106B, and causes the rotor shaft 113 to magnetically float in the axial direction and hold the space in a non-contact manner. ing.

  The motor 121 includes a plurality of magnetic poles arranged circumferentially so as to surround the rotor shaft 113. Each magnetic pole is controlled by the control device 200 so as to rotationally drive the rotor shaft 113 through electromagnetic force acting between the rotor shaft 113 and the magnetic pole.

  A plurality of fixed blades 123a, 123b, 123c,... Are arranged with a slight gap from the rotor blades 102a, 102b, 102c,. The rotor blades 102a, 102b, 102c,... Are each inclined at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113 in order to transfer exhaust gas molecules downward by collision.

Similarly, the fixed blades 123 are also formed to be inclined at a predetermined angle from a plane perpendicular to the axis of the rotor shaft 113, and are arranged alternately with the stages of the rotary blades 102 toward the inside of the outer cylinder 127. ing.
And one end of the fixed wing | blade 123 is supported in the state inserted and inserted between the several fixed wing | blade spacer 125a, 125b, 125c ... stacked.

  The fixed blade spacer 125 is a ring-shaped member and is made of a metal such as a metal such as aluminum, iron, stainless steel, or copper, or an alloy containing these metals as components.

  An outer cylinder 127 is fixed to the outer periphery of the fixed blade spacer 125 with a slight gap. A base portion 129 is disposed at the bottom of the outer cylinder 127, and a threaded spacer 131 is disposed between the lower portion of the fixed blade spacer 125 and the base portion 129. An exhaust port 133 is formed below the threaded spacer 131 in the base portion 129 and communicates with the outside.

The threaded spacer 131 is a cylindrical member made of metal such as aluminum, copper, stainless steel, iron, or an alloy containing these metals as a component, and a plurality of spiral thread grooves 131a are formed on the inner peripheral surface thereof. It is marked.
The direction of the spiral of the thread groove 131 a is a direction in which molecules of the exhaust gas move toward the exhaust port 133 when the molecules of the exhaust gas move in the rotation direction of the rotating body 103.

  A rotating blade 102d is suspended from the lowermost portion of the rotating body 103 following the rotating blades 102a, 102b, 102c. The outer peripheral surface of the rotor blade 102d is cylindrical and protrudes toward the inner peripheral surface of the threaded spacer 131, and is adjacent to the inner peripheral surface of the threaded spacer 131 with a predetermined gap. Yes.

  The base portion 129 is a disk-like member that constitutes the base portion of the turbo molecular pump 10, and is generally made of a metal such as iron, aluminum, or stainless steel.

  Since the base part 129 physically holds the turbo molecular pump 10 and also has a function of a heat conduction path, a metal having rigidity such as iron, aluminum and copper and high thermal conductivity is used. Is desirable.

  In such a configuration, when the rotary blade 102 is driven by the motor 121 and rotates together with the rotor shaft 113, exhaust gas from the chamber is sucked through the intake port 101 by the action of the rotary blade 102 and the fixed blade 123.

  Exhaust gas sucked from the inlet 101 passes between the rotary blade 102 and the fixed blade 123 and is transferred to the base portion 129. At this time, the temperature of the rotor blades 102 increases due to frictional heat generated when the exhaust gas contacts or collides with the rotor blades 102, conduction or radiation of heat generated by the motor 121, etc. It is transmitted to the fixed wing 123 side by conduction with gas molecules of the exhaust gas.

The fixed blade spacers 125 are joined to each other at the outer peripheral portion, and heat received by the fixed blade 123 from the rotor blade 102, frictional heat generated when exhaust gas contacts or collides with the fixed blade 123, and the like are used for the outer cylinder 127 and the screw. This is transmitted to the attached spacer 131.
The exhaust gas transferred to the threaded spacer 131 is sent to the exhaust port 133 while being guided by the screw groove 131a.

Next, the board | substrate structure in the control apparatus 200 is demonstrated.
An internal block diagram of the control device 200 is shown in FIG.
As shown in FIG. 2, a drive current amplifier 5 including an FET as a switching element for causing a current to flow to each of the electromagnets 104, 105, 106 of the magnetic bearing on the power substrate 21 constituted by one substrate. And a drive current amplifier 7 including an FET as a switching element for causing a current to flow to the three-phase motor 121. Here, the drive current amplifier 5 corresponds to a magnetic bearing drive current amplifier, and the drive current amplifier 7 corresponds to a motor drive current amplifier.
That is, the power substrate 21 includes current amplification and driving electronic elements (power elements) that require a current of 200 mA or more. A current of about 10 amperes flows through the power element when the motor 121 is accelerated.

  On the other hand, on the control board 23 composed of a single board, a magnetic bearing levitation composed of a digital circuit (including a CPU and DSP (Digital Signal Processor)) and a sensor circuit including a magnetic circuit levitation control. A weak electric element including a digital circuit (including a CPU and a DSP) and a sensor circuit necessary for the control 6 and the rotational speed control 8 for the motor 121 is mounted. On the control board 23, a user interface 9 and an I / O port 11 made of weak electric elements are also mounted, and signals are exchanged with the user 4.

The user interface 9 monitors the states of the magnetic bearings 104, 105, 106 and the motor 121 and performs notification control for the user 4.
In other words, the control board 23 is a collection of control electronic elements (weak current elements) in which a weak current of less than 200 mA flows.

  Further, FIG. 3 shows the arrangement of the substrates inside the control device 200. The power board 21 is fixed to the casing 12 of the control device 200 via a heat dissipation sheet 24. Thereby, the heat generated in the power board 21 is transmitted to the outside through the casing 12 and is naturally cooled. That is, the housing 12 plays a role as a heat sink.

  In this configuration, the conventional board arrangement of FIGS. 4 and 5 requires two sheets of the AMB board 1, the motor board 2, and the interface board 3. In this embodiment, two boards of the power board 21 and the control board 23 are used. Just do it. For this reason, the number of substrates to be accommodated is smaller than in the prior art, and the control device 200 can be designed to be small. In addition, the number of connectors is reduced, and the size can be reduced accordingly.

  Only the power board 21 needs to dissipate heat, and only one heat dissipating sheet 24 is sufficient. Conventionally, the two substrates of the AMB substrate 1 and the motor substrate 2 including the power element are likely to break down due to heat, and it is necessary to prepare these two types of substrates for replacement. On the other hand, in the present embodiment, since the power element is included only in the power board 21, only the power board 21 has heat and thus has a short life and easily breaks down. Therefore, only one type of substrate of the power substrate 21 is prepared for replacement. Since only one type of substrate needs to be mass-produced, repair costs can be reduced.

Since the control board 23 generates a small amount of heat and is not affected by heat, the life of the board is long and there is almost no failure. Natural air cooling is sufficient.
Further, conventionally, since it has been necessary to arrange the two boards of the AMB board 1 and the motor board 2 in the control device in consideration of heat radiation, the layout is difficult. Since there is only one place to install, heat radiation can be concentrated, layout is simple, and workability is improved.

  The control board 23 is supported by a rod (not shown) standing from the housing 12. For this reason, it is possible to perform the work of attaching the board and the connector while the operator confirms with the eye with the case lid 14 opened. The assembly is one way. Therefore, the installation work is easy and the length of the cable can be minimized.

Therefore, since there is a margin in the length of the cable as in the prior art, when the lid of the casing is closed, the cable is sandwiched between the lid and the casing, and the cable cannot be easily stored.
In addition, since the installation work can be performed while visually confirming by the operator, the height of the circuit is, for example, within the range of the height of the element 25 mounted on the power board 21 as shown in FIG. A part or all of the height of the element 26 mounted on the control board 23 can be included. That is, the layout can be designed so that components between the boards do not interfere. Therefore, the height of the control device 200 can be kept low. As a result, the height of the conventional control device 200 can be reduced to less than half, in addition to the fact that the size can be reduced by reducing the number of the substrates described above.

  Further, conventionally, since the two substrates, the AMB substrate 1 and the motor substrate 2, are both mounted with elements that require electric power, the width of the copper foil of the wiring pattern is wide. On the other hand, in the control board 23 of this embodiment, since the amount of current flowing through the board is small, the width of the copper foil of the wiring pattern can be narrowed. For this reason, electronic devices that can be mounted can be mounted at high density.

  Moreover, also about the power board 21, the width | variety of the copper foil of a wiring pattern was narrowed, and the thickness of the copper foil was thickened. That is, the thickness of the conventional copper foil is 18 μm and the width is wide. In this embodiment, the thickness of the copper foil is 35 μm and the width is narrow. In this way, power elements can be mounted at a higher density than before.

  In the present embodiment, the user interface 9 and the I / O port 11 are described as being mounted on the control board 23, but the user interface 9 and the I / O port 11 may be different from the control board 23. Good. Even in this case, there is almost no heat generation from the user interface 9 and the I / O port 11, so that the heat dissipation sheet can be concentrated at only one place on the power board 21. For this reason, the control apparatus 200 can be designed smaller than before. In this case, the substrate can be supported by the rod in the same manner as the control substrate 23. For this reason, it is possible to perform the work of attaching the board and the connector while the operator confirms with the eye with the case lid 14 opened. The assembly is one way. Therefore, the installation work is easy and the length of the cable can be minimized.

The control device, power board, control board, and vacuum pump according to the present invention can be applied to an all-blade type vacuum pump in addition to the composite type vacuum pump described above.
Moreover, you may make it the structure which combines embodiment and each modification of this invention as needed. The present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

DESCRIPTION OF SYMBOLS 1 AMB board 2 Motor board 3 Interface board 4 User 5, 7 Drive current amplifier 6 Magnetic bearing levitation control 8 Rotational speed control 9 User interface 10 Turbo molecular pump 11 I / O port 12 Case 21 Power board 23 Control board 24 Heat dissipation sheet 100 Pump body 104 Upper radial electromagnet 105 Lower radial electromagnet 106 Axial electromagnet 121 Motor 200 Control device

Claims (10)

A power board equipped with a drive current amplifier for a magnetic bearing that sends current to the magnetic bearing and a drive current amplifier for the motor that sends current to the motor;
A control board responsible for levitation control by the magnetic bearing and rotation speed control of the motor;
A control device comprising: a housing for housing the control board and the power board. The control board further includes a user interface for monitoring and controlling the status of the magnetic bearing and the motor, and
The control apparatus according to claim 1, further comprising a transmission unit that performs communication with a user.   The control device according to claim 1, wherein a heat dissipation unit is interposed between the power board and the housing.   The part of or all of the height of at least one electronic element mounted on the control board is included in the range of the maximum height among the electronic elements mounted on the power board. 4. The control device according to any one of 3.   The control device according to claim 1, wherein the control board is supported inside the housing via a positioning unit.   The control device according to claim 1, wherein a thickness of the copper foil forming the wiring pattern of the power board is 35 μm or more. A current of 200 mA or more is passed through the electronic elements mounted on the power board,
On the other hand, the control device according to any one of claims 1 to 6, wherein a current of less than 200 mA is passed through an electronic element mounted on the control board.   A power board mounted on the control device according to claim 1 and including a power element.   A control board mounted on the control device according to claim 1 and having a control system light-electric element including at least one of a digital circuit and a sensor circuit.   A vacuum pump to which the control device according to any one of claims 1 to 7 is applied.

Images