JP2014234828A - Seal unit degradation warning system, transport device, and semiconductor manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seal unit, a transport device, and a semiconductor manufacturing apparatus capable of suppressing a situation in which an exhaust pump stops while abrasion of a contact seal develops.SOLUTION: A degradation warning system for a seal unit isolating two spaces at different pressures comprises: a housing; a movable member penetrating the housing, and arranged to have a gap with the housing; a contact seal hermetically closing the gap; a noncontact seal hermetically sealing the gap at a different position from the contact seal; an attraction groove that is a recess of a surface of the housing located between the contact seal and the noncontact seal; a discharge path connected to the attraction groove and discharging gas from the attraction groove; an attraction unit attracting the gas in the discharge path; and a control unit transmitting a signal in response to a change in a pressure in the discharge path. A position at which the noncontact seal is arranged is closer to the lower-pressure space out of the two spaces with respect to a position at which the contact seal is arranged.

Description

  The present invention relates to a seal unit deterioration warning system, a transfer device, and a semiconductor manufacturing apparatus.

  In recent years, a seal unit that seals a gap with a non-contact type seal is known. However, when the gap is sealed with a non-contact type seal, there is a problem that the airtight performance of the seal unit is abruptly lowered when the exhaust pump is stopped. On the other hand, the technique described in Patent Document 1 is known. On the other hand, Patent Document 2 discloses a seal unit having a non-contact seal and a contact seal.

JP 2004-44629 A JP 2007-9939 A

  The contact-type seal described in Patent Document 2 is in contact with a moving member. For this reason, the contact-type seal may be worn. Therefore, before the contact seal wears out, the contact seal needs to be maintained by replacement or repair. However, when the exhaust pump is stopped in a state where the wear of the contact-type seal has progressed, the airtight performance of the entire seal unit is rapidly lowered. For this reason, the apparatus which can suppress the situation where an exhaust pump stops in the state which abrasion of a contact-type seal advanced is desired.

  The present invention has been made in view of the above, and provides a deterioration warning system for a seal unit, a transfer device, and a semiconductor manufacturing device capable of suppressing a situation in which an exhaust pump stops in a state where contact-type seal wear has progressed. The purpose is to provide.

  To achieve the above object, a deterioration warning system for a seal unit according to the present invention is a deterioration warning system for a seal unit that separates two spaces having different pressures, and includes a housing, a housing penetrating through the housing, A movable member disposed with a gap therebetween, a contact seal that seals the gap, a non-contact seal that seals the gap at a position different from the contact seal, and the contact seal and the non-contact A suction groove that is a recess in the surface of the housing located between the suction seal, a discharge path that is connected to the suction groove and serves as a passage for discharging gas from the suction groove, and a gas in the discharge path A position where the non-contact type seal is disposed at the position where the non-contact type seal is disposed. Than placed are located, characterized in that it is a position closer to the low-pressure space of the two spaces.

  When the wear of the contact seal progresses, more gas passes through the contact seal. For this reason, the gas flowing into the discharge path connected to the gap at the position between the contact seal and the non-contact seal also increases, and the pressure in the discharge path increases. The seal unit deterioration warning system according to the present invention includes a control unit that transmits a signal in accordance with a change in pressure in the discharge passage. Thereby, the deterioration warning system for the seal unit according to the present invention can notify a person of the progress of wear of the contact seal based on the change in the pressure in the discharge path. Therefore, the deterioration warning system for the seal unit according to the present invention can suppress a situation in which the exhaust pump stops in a state where the wear of the contact type seal has progressed.

  In the deterioration warning system for a seal unit according to the present invention, the control unit includes a storage device that stores a threshold value, and a central processing unit that compares the pressure in the discharge passage with the threshold value. It is preferable to have. By doing in this way, a control part compares the pressure in a discharge channel with a threshold value, and transmits a signal when the pressure in a discharge channel exceeds a threshold value. In addition, since the threshold value can be changed, the deterioration warning system for the seal unit according to the present invention informs humans of the progress of wear of the contact-type seal in accordance with the high hermetic performance required for the seal unit. The time can be adjusted appropriately. Therefore, the deterioration warning system for the seal unit according to the present invention can suppress a situation in which the exhaust pump stops in a state where the wear of the contact type seal has progressed.

  In the deterioration warning system for a seal unit according to the present invention, the movable member is a member that rotates around a rotation axis parallel to a direction penetrating the housing, has a plate-like flange portion, and the flange portion; It is preferable that the gap is provided between the housing and the housing. By doing in this way, the clearance gap between a flange part and a housing turns into a clearance gap which has height in a rotating shaft direction. Thereby, the clearance gap between a flange part and a housing can improve the dimensional accuracy of height compared with the clearance gap which has height in the orthogonal direction with respect to a rotating shaft. For this reason, the airtight performance of the non-contact type seal which is a minute gap between the flange portion and the housing is improved. Therefore, since the deterioration warning system for the seal unit according to the present invention can detect the progress of wear of the contact seal more accurately, the situation where the exhaust pump stops in a state where the wear of the contact seal has progressed can be suppressed. .

  In the deterioration warning system for a seal unit according to the present invention, an introduction groove that is a recess in the surface of the housing located between the contact seal and the non-contact seal, and the introduction groove connected to the introduction groove It is preferable to include an introduction path serving as a passage for introducing gas into the gas. By doing in this way, the quantity of the gas which distribute | circulates an introduction groove | channel and a suction groove | channel increases. For this reason, even if foreign matter generated due to wear of the contact-type seal enters between the contact-type seal and the non-contact-type seal, the foreign matter is easily removed to the outside of the housing through the discharge path. As a result, the deterioration warning system for the seal unit according to the present invention prevents the foreign matter from passing through the non-contact type seal and entering the low-pressure space side, while exhausting the contact type seal, The situation that the pump stops can be suppressed.

  In the deterioration warning system for a seal unit according to the present invention, it is preferable that the introduction groove is a dent on the surface of the housing located between the contact seal and the suction groove. By doing so, the suction groove is arranged on the lower pressure side than the introduction groove. For this reason, the gas flow from the introduction groove to the suction groove is stabilized. As a result, the deterioration warning system for the seal unit according to the present invention prevents the foreign matter from passing through the non-contact type seal and entering the low-pressure space side, while exhausting the contact type seal, The situation that the pump stops can be suppressed.

  Moreover, the conveying apparatus which concerns on this invention is equipped with said deterioration warning system of a seal unit, It is characterized by the above-mentioned.

  A semiconductor manufacturing apparatus according to the present invention includes the above-described seal unit deterioration warning system.

  The deterioration warning system for a seal unit, the transfer apparatus, and the semiconductor manufacturing apparatus according to the present invention can suppress a situation in which the exhaust pump stops in a state in which the wear of the contact seal progresses.

FIG. 1 is a diagram showing a semiconductor manufacturing apparatus equipped with a seal unit deterioration warning system. FIG. 2 is a plan view of the housing shown in FIG. 1 viewed from the housing side. FIG. 3 is an enlarged view of a cross section of the seal unit shown in FIG. FIG. 4 is a flowchart of a method for detecting the progress of wear of a contact-type seal using a deterioration warning system. FIG. 5 is an explanatory view showing a modification of the semiconductor manufacturing apparatus shown in FIG. FIG. 6 is an enlarged view of a cross section of the seal unit shown in FIG. FIG. 7 is a view showing a seal unit when the contact-type seal and the non-contact-type seal are arranged at different positions in the axial direction.

  Hereinafter, a mode for carrying out a seal unit deterioration warning system, a transfer device, or a semiconductor manufacturing device (hereinafter referred to as an embodiment) will be described in detail with reference to the drawings. In addition, this invention is not limited by the following embodiment. In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be appropriately combined.

[Semiconductor manufacturing equipment]
FIG. 1 is a diagram showing a semiconductor manufacturing apparatus equipped with a seal unit deterioration warning system. The semiconductor manufacturing apparatus 100 includes a seal unit 1, a housing 10, and a driving device 8. The semiconductor manufacturing apparatus 100 needs to move an object (for example, a semiconductor) in the internal space V after the internal space V of the housing 10 is in a vacuum environment, a reduced pressure environment, and a process gas filling environment. However, if a transfer device including the driving device 8 and a movable member to be described later is installed in the internal space V for movement, foreign matter may be generated by the operation of the driving device 8, which may not be preferable. Therefore, the semiconductor manufacturing apparatus 100 installs the driving device 8 in the external space E while leaving the movable member in the internal space V. In order to transmit the power of the drive device 8 installed in the external space E to the internal space V while separating the internal space V and the external space E, the seal unit 1 is required. The drive device 8 is, for example, a direct drive motor, a drive device using a belt drive, a linear motor, a servo motor, or the like.

[Seal unit]
The seal unit 1 is a sealing device that separates the internal space V of the housing 10 from the external space E of the housing 10. The seal unit 1 is applied to, for example, a flat panel display manufacturing apparatus in addition to a semiconductor manufacturing apparatus used in a special environment such as a vacuum casing. Here, as an example, when the housing 10 has the opening 10e, an example in which the seal unit 1 seals the opening 10e will be described. As shown in FIG. 1, the seal unit 1 includes a housing 2, a movable member 3, and a bearing 13. In addition, the dashed-dotted line in the figure has shown the axis | shaft O which is a rotating shaft of the movable member 3 of the seal unit 1. FIG. 1 is a cross-sectional view of the semiconductor manufacturing apparatus 100 taken along a plane including the axis O.

  FIG. 2 is a plan view of the housing shown in FIG. 1 viewed from the housing side. For example, the housing 2 has a cylindrical opening 26 and has a cylindrical shape as a whole. Moreover, the housing | casing 10 has the circular opening part 10e. The housing 2 includes a flange portion 21 that is fastened to the housing 10 and a bearing holding portion 22 that holds the bearing 13. The flange portion 21 and the bearing holding portion 22 are arranged in the order of the flange portion 21 and the bearing holding portion 22 from the side close to the housing 10 along the axis O direction. For example, the flange portion 21 has a plate shape and a disk shape having a larger area than the opening portion 10e. The housing 2 is fixed to the housing 10 by applying the flange portion 21 so as to cover the opening 10e of the housing 10 from the outside of the housing 10 and fastening the flange portion 21 and the wall surface of the housing 10 with bolts. Yes. Thereby, the housing 2 can block the opening 10 e of the housing 10 from the outside of the housing 10.

  As shown in FIG. 2, the annular groove 25, the suction groove 27, and the annular groove 211 are annular recesses on the surface of the flange portion 21 that faces the housing 10. The annular groove 25, the suction groove 27, and the annular groove 211 are formed so as to draw concentric circles with the axis O as the center. Further, in the flange portion 21, the suction groove 27 is formed radially outside the annular groove 25, and the annular groove 211 is formed radially outside the suction groove 27. The annular groove 211 is formed in the flange portion 21 at a position where the housing 10 and the flange portion 21 overlap in the axis O direction. The annular groove 25, the suction groove 27, and the annular groove 211 are used for causing the seal unit 1 to exhibit airtight performance, as will be described later.

  The movable member 3 is a member that rotates about the axis O. The movable member 3 includes a flange portion 31, a table 32, and a shaft portion 33. The shaft 33 is inserted into the opening 26 of the housing 2 along the axis O direction and penetrates the housing 2. One end portion of the shaft portion 33 is located in the internal space V, and the other end portion is located in the external space E. The flange portion 31 is plate-shaped, and a disk-shaped plate material is attached to the shaft portion 33 and integrated with the shaft portion 33. The flange portion 31 is disposed so as to face the flange portion 21 in the axis O direction. The outer periphery of the flange portion 31 is indicated by a two-dot chain line shown in FIG. 2 and is smaller than the outer periphery of the flange portion 21 and larger than the outer periphery of the opening portion 26. For this reason, the flange portion 21 and the flange portion 31 overlap each other in the axis O direction in a range outside the opening portion 26 in the radial direction and the flange portion 31 in the radial direction, and the overlapping portion is located between the flange portion 21 and the flange portion 31. A gap is formed. Further, the end portion of the shaft portion 33 on the inner space V side is connected to the bottom surface of the table 32, and the end portion of the shaft portion 33 on the outer space E side is connected to the driving device 8. For example, the movable member 3 is powered by a driving device 8 that includes a motor 81 and a shaft 82. By connecting the end portion of the shaft portion 33 on the outer space E side to the shaft 82, torque generated by the motor 81 is transmitted to the movable member 3 via the shaft 82.

  FIG. 3 is an enlarged view of a cross section of the seal unit 1 shown in FIG. For example, the movable member 3 is supported by the bearing 13 so as to be rotatable with respect to the housing 2. As shown in FIG. 3, the outer ring 13 o of the bearing 13 is fitted into a recess 23 formed in the inner wall of the bearing holding portion 22 and is positioned in the axis O direction. The housing 2 has an outer ring presser 14. And the bearing holding | maintenance part 22 has the notch part 24 in the edge part on the opposite side to the flange part 21 in the axis | shaft O direction. The outer ring presser 14 is fitted in the notch 24 and is fixed to the bearing holding part 22 by bolt fastening, thereby supporting the outer ring 13o in the axis O direction. In this way, the outer ring 13o is fixed to the housing 2.

  The movable member 3 includes cylindrical spacers 12 and 16 and an inner ring fixing nut 15. The spacer 12 is fitted on the outer periphery of the shaft portion 33 and is disposed between the flange portion 31 and the inner ring 13i. The spacer 16 is fitted on the outer periphery of the shaft portion 33 and is disposed so as to sandwich the inner ring 13 i from the axis O direction together with the spacer 12. Further, a screw thread is formed at the end of the shaft portion 33 on the outer space E side. The inner ring fixing nut 15 is fixed by being fitted to the screw thread, thereby fixing the inner ring 13 i to the movable member 3 via the spacer 16. As a result, the inner ring 13 i of the bearing 13 is sandwiched between the spacer 12 and the spacer 16 and is fitted to the outer periphery of the shaft portion 33. Further, since the spacer 12 regulates the length of the flange portion 31 and the inner ring 13i, when the dimension of the spacer 12 in the axis O direction is determined, the position of the flange portion 31 in the axis O direction is adjusted.

[Seal structure]
The internal space V of the housing 10 and the external space E of the housing 10 are different environments. For example, in the semiconductor manufacturing apparatus 100, the internal space V is set to a vacuum environment, a reduced pressure environment, a process gas filling environment, or the like. The external space E is, for example, an environment into which outside air is introduced. For this reason, the internal space V and the external space E are two spaces having different pressures, and the internal space V has a lower pressure than the external space E.

  As described above, the outer ring 13 o of the bearing 13 is fixed to the housing 2, and the inner ring 13 i is fixed to the movable member 3. The movable member 3 is disposed with a space C between the housing 2 and the housing 2 so as not to contact the housing 2 at portions other than the bearings 13 as shown in FIG. Since the outside air in the external space E flows through the bearing 13 into the space C, the space C has the same pressure as the external space E. Since the gas moves from the high pressure side to the low pressure side, the outside air in the space C tends to flow into the internal space V through the gap between the flange portion 21 and the flange portion 31.

  The seal unit 1 includes at least two types of seals, that is, a contact seal 4 and a non-contact seal 5 in order to seal the housing 10 having the special environment as described above. Since the seal unit 1 has the contact seal 4, the contact seal 4 may be worn. For this reason, as shown in FIG. 2, the contact-type seal | sticker 4 and the non-contact-type seal | sticker 5 are cyclic | annular, and are arrange | positioned in a different position. The position where the contact-type seal 4 is arranged is a position closer to the space C, which is the same pressure as the external space E, than the position where the non-contact-type seal 5 is arranged. That is, the contact type seal 4 is arranged on the high pressure side, and the non-contact type seal 5 is arranged on the low pressure side. Thereby, even when wear of the contact-type seal 4 proceeds, the non-contact-type seal 5 is arranged on the low-pressure side, so that the airtight performance of the seal unit 1 is maintained.

  As shown in FIGS. 1 and 2, the contact-type seal 4 is fitted in an annular groove 25 formed on the surface of the flange portion 21, contacts the flange portion 31, and a gap between the flange portion 21 and the flange portion 31. To seal. Since the contact-type seal 4 is fitted into the annular groove 25, the contact-type seal 4 has a shape that draws a circle around the axis O. For example, the contact-type seal 4 is a lip packing, and is an elastic seal made of resin, rubber material, or the like. The contact seal 4 may be an O-ring or the like. Since the contact seal 4 is an elastic seal, the contact seal 4 contacts the flange portion 31 while being pressed against the flange portion 31. For this reason, the contact-type seal 4 seals the gap between the flange portion 21 and the flange portion 31. In addition, it is preferable that the contact-type seal | sticker 4 can exhibit the sealing function, without requiring additional actions, such as an external power supply, high pressure gas, and vacuum exhaust, for example.

  As shown in FIG. 3, the non-contact type seal 5 is a minute gap having a height Δ1 of about 10 μm, for example. The minute gap has a predetermined width in the radial direction of the flange portion 21. Further, as shown in FIG. 2, the non-contact seal 5 is disposed along the outer periphery of the suction groove 27. For this reason, the non-contact seal 5 has a shape that draws a circle with the axis O as the center.

  The seal unit 1 includes a discharge path 6 and a suction unit 20. The discharge path 6 is a path for discharging gas from the suction groove 27, and includes a vent hole 61 and a pipe 62. The ventilation hole 61 is an opening that penetrates the housing 2 from the outside of the housing 2 and is connected to the suction groove 61. One end of the pipe 62 is connected to the vent hole 61, and the other end of the pipe 62 is connected to the suction unit 20. The suction unit 20 includes a pump, and exhausts gas from the suction groove 27 through the pipe 62 and the vent hole 61. With such a configuration, the non-contact type seal 5 exhibits airtight performance as a minute gap in the differential exhaust seal. Although there is one suction groove 27 and one discharge path 6 according to the present embodiment, there may be a plurality of suction grooves 27 and discharge paths 6.

  In the seal unit 1, the contact seal 4 is disposed on the high pressure side, and the non-contact seal 5 is disposed on the low pressure side. Outside air in the external space E, that is, outside air in the space C, may pass through the contact seal 4 and enter the suction groove 27. The suction unit 20 discharges a slight amount of outside air that has passed through the contact seal 4 and entered the suction groove 27. At this time, since the non-contact type seal 5 is a minute gap having a height Δ1 of about 10 μm, most of the outside air flowing into the suction groove 27 is discharged to the outside of the housing 2 through the discharge path 6. As a result, the amount of outside air that passes through the non-contact type seal 5 and flows into the internal space V becomes extremely small. Therefore, the internal space V can obtain an airtightly isolated state. Thus, the non-contact seal 5 seals the gap between the flange portion 21 and the flange portion 31 without contacting the flange portion 31.

  As described above, the contact-type seal 4 and the non-contact-type seal 5 have shapes that draw a circle around the axis O at different positions. That is, the contact seal 4 and the non-contact seal 5 are arranged so as to draw a concentric circle with the axis O as the center. For this reason, the distance between the contact-type seal 4 and the non-contact-type seal 5 is stabilized regardless of the circumferential position of the flange portion 21, so that the amount of outside air entering the suction groove 27 is stabilized. Therefore, the seal unit 1 can maintain high airtight performance regardless of the circumferential position of the flange portion 21.

  Further, in the flange portion 21, the suction groove 27 is formed on the radially outer side from the annular groove 25. Further, in the flange portion 21, the suction groove 27 and the annular groove 25 are separated in the radial direction. For this reason, as shown in FIG. 3, a narrowed portion N <b> 1 is formed between the suction groove 27 and the annular groove 25. For example, the narrowed portion N1 is a minute gap having a height Δ2 of about 10 μm. Here, the heights Δ1 and Δ2 will be described. In order for the non-contact seal 5 to exhibit hermetic performance, the height Δ1 needs to be about 10 μm. On the other hand, the narrowed portion N1 may be a gap having a height Δ2 of 0.1 mm or more, for example. However, by setting the narrowed portion N1 as a gap having a height Δ2 of about 10 μm, foreign matter generated due to wear of the contact seal 4 is less likely to enter the suction groove 27. Accordingly, the foreign matter generated when the contact-type seal 4 is worn is less likely to enter the internal space V. In addition, although suitable height (DELTA) 1 for the non-contact-type seal | sticker 5 to exhibit airtight performance changes with the shape of the non-contact-type seal | sticker 5 whole and the performance of the suction part 20, it is preferable that they are 5 micrometers or more and 30 micrometers or less, More preferably, it is 5 μm or more and 15 μm or less.

  Further, the flange portion 21 of the housing 2 has an annular groove 211 at a contact portion with the housing 10, and an O-ring 212 is disposed in the annular groove 211. Thereby, the clearance gap between the flange part 21 and the housing | casing 10 is sealed.

[Deterioration warning system]
In the configuration having the contact-type seal 4 as described above, the contact-type seal 4 may be worn due to contact with the movable member 3. However, when the suction part 20 stops in a state where the wear of the contact-type seal 4 has progressed, the airtight performance of the entire seal unit 1 is drastically lowered. Therefore, before the contact-type seal 4 wears, the contact-type seal 4 needs to be maintained by replacement or repair. For this reason, the seal unit 1 includes a deterioration warning device 9 in order to suppress a situation in which the suction unit 20 stops in a state in which the wear of the contact seal 4 has progressed.

  The deterioration warning device 9 is a device for transmitting a signal according to a change in pressure in the discharge path 6. The degradation warning device 9 notifies a human being that the wear of the contact-type seal 4 is progressing by transmitting a signal. As shown in FIG. 1, the deterioration warning device 9 includes a pressure gauge 91, a control unit 92, and a signal unit 93. For example, the pressure gauge 91 is connected to the pipe 62 at a position between the vent hole 61 and the suction part 20 and always measures the pressure in the pipe 62. Note that the pressure gauge 91 may measure the pressure in the pipe 62 at regular intervals. For example, the pressure gauge 91 is a diaphragm pressure gauge. A diaphragm pressure gauge is a device that has a diaphragm, which is a plate-like member that is easily bent, and measures the pressure by reading the amount of bending of the diaphragm that deforms according to the pressure. The pressure gauge 91 may be one using a Bourdon tube pressure gauge or the like.

  The control unit 92 will be described. The control unit 92 is, for example, a PLC (Programmable Logic Controller). The PLC is a control device that changes an output signal to be output in accordance with a change in an input signal that is input. The control unit 92 includes an input circuit 92a, a central processing unit (CPU) 92b that is a central processing unit, a memory 92c that is a storage device, and an output circuit 92d. Conditions for changing the output signal are stored as a program in the memory 92c. The program stored in the memory 92c is described, for example, as a ladder diagram that symbolizes an electrical circuit diagram. The memory 92c stores a threshold value. The CPU 92b compares the input signal with the threshold value according to the program stored in the memory 92c, and changes the output signal according to the comparison result. In addition, the control unit 92 can change the condition for changing the output signal by changing the program or threshold value stored in the memory 92c.

  In the present embodiment, the input signal input to the control unit 92 changes according to the pressure value in the pipe 62 measured by the pressure gauge 91. The pressure value in the pipe 62 measured by the pressure gauge 91 is converted into an electric signal and then sent as an input signal to the CPU 92b via the input circuit 92a. Since the pressure gauge 91 always measures the pressure in the pipe 62, the pressure value as an input signal is always sent to the CPU 92b. While receiving the pressure value in the pipe 62, the CPU 92b compares the pressure value in the pipe 62 with the threshold value stored in the memory 92c. When the wear of the contact seal 4 is not progressing, the pressure in the pipe 62 is a negative pressure and is kept within a predetermined range. On the other hand, when wear of the contact seal 4 progresses, the outside air in the space C easily flows into the suction groove 27, so that the pressure in the pipe 62 increases. For this reason, the threshold value is set on the assumption of the pressure value in the pipe 62 when the wear of the contact-type seal 4 has progressed, and thus the threshold value is larger than the predetermined range. Note that the threshold value to be set varies depending on the shape of the pipe 62 and the pump characteristics of the suction unit 20, and therefore needs to be adjusted according to the shape of the pipe 62 and the pump characteristics of the suction unit 20.

  The CPU 92b transmits an output signal according to the comparison result between the pressure in the pipe 62 and the threshold value. For example, the CPU 92b transmits an output signal to the signal unit 93 via the output circuit 92d when the pressure in the pipe 62 exceeds a threshold value. And CPU92b does not transmit an output signal, when the pressure in the piping 62 is below a threshold value. When receiving the output signal, the signal unit 93 transmits a signal that can be perceived by humans. The signal transmitted from the signal unit 93 is not particularly limited as long as it can be perceived by humans. For example, the signal transmitted by the signal unit 93 may be a warning text display or a warning sound. Thereby, the signal part 93 can notify a human being that the pressure in the piping 62 has exceeded the threshold value. Therefore, the deterioration warning system of the seal unit 1 can suppress a situation in which the suction unit 20 stops in a state where the wear of the contact seal 4 has progressed. The CPU 92b continues to send an output signal to the signal unit 93 via the output circuit 92d when the pressure in the pipe 62 is equal to or lower than the threshold value, and the pressure in the pipe 62 exceeds the threshold value. In some cases, the output signal may not be transmitted. The signal unit 93 transmits a signal that can be perceived by humans when the output signal is interrupted.

  Further, the CPU 92b may safely stop the driving device 8 according to the comparison result between the pressure in the pipe 62 and the threshold value. For example, the output circuit 92d and the driver of the driving device 8 may be connected, and the CPU 92b may transmit an output signal for safely stopping the operation of the driving device 8 to the driver of the driving device 8. Further, the CPU 92b may safely stop the device that adjusts the environment of the internal space V according to the comparison result between the pressure in the pipe 62 and the threshold value. The device for adjusting the environment of the internal space V is, for example, a pump that discharges gas in the internal space V. For example, the output circuit 92d and the pump control device may be connected, and the CPU 92b may send an output signal for safely stopping the pump operation to the pump control device. The pump control device is, for example, a PLC. When the CPU 92b safely stops the operation of at least one of the drive device 8 and the device that adjusts the environment of the internal space V, the CPU 92b also transmits an output signal to the signal unit 93 via the output circuit 92d. When receiving the output signal, the signal unit 93 transmits a signal that can be perceived by humans. Thereby, the signal part 93 can notify a human being that the pressure in the piping 62 exceeds a threshold value, and at least one of the apparatus which adjusts the environment of the drive device 8 and the internal space V is a stop state. Therefore, the deterioration warning system of the seal unit 1 can suppress a situation in which the suction unit 20 stops in a state where the wear of the contact seal 4 has progressed. And the semiconductor manufacturing apparatus 100 provided with the deterioration warning system of the seal unit 1 or the transfer device provided with the deterioration warning system of the seal unit 1 has a situation in which the suction unit 20 stops in a state in which the wear of the contact seal 4 has progressed. Can be suppressed. The CPU 92b may send an output signal to the signal unit 93 via the output circuit 92d after at least one of the driving device 8 and the device that adjusts the environment of the internal space V is safely stopped. For example, the input circuit 92 a and the driver of the driving device 8 are connected, and the CPU 92 b transmits an output signal to the signal unit 93 after receiving a signal indicating the stop state of the driving device 8 from the driver of the driving device 8. May be.

  As a modification of the deterioration detection system, the output circuit 92d may be connected to a control device for controlling the drive device 8. For example, the control device for controlling the drive device 8 is a PLC. A control device for controlling the driving device 8 is connected to a driver of the driving device 8. The CPU 92b transmits an output signal to the control device for controlling the drive device 8, and the control device for controlling the drive device 8 transmits the output signal to the driver of the drive device 8, thereby controlling the drive device 8. Therefore, the control device for stopping the operation of the drive device 8 safely.

[Deterioration detection method]
FIG. 4 is a flowchart of a method for detecting the progress of wear of a contact-type seal using a deterioration warning system. First, the suction unit 20 starts sucking the gas in the suction groove 27 (step S1). Thereby, the non-contact seal 5 begins to exhibit airtight performance. Therefore, the gap between the flange portion 21 and the flange portion 31 is sealed with the contact seal 4 and the non-contact seal 5.

  Next, the power from the drive device 8 is obtained, and the operation of the movable member 3 is started (step S2).

  Immediately after or simultaneously with the start of the operation of the movable member 3, the pressure gauge 91 starts measuring the pressure in the pipe 62 (step S3). Note that the pressure gauge 91 may start measuring the pressure in the pipe 62 before the movable member 3 operates.

  Next, the pressure value in the pipe 62 measured by the pressure gauge 91 is converted into an electric signal and then sent to the CPU 92b via the input circuit 92a of the control unit 92. The CPU 92b compares the pressure value in the pipe 62 with the threshold value stored in the memory 92c (step S4).

  Next, when the pressure value in the pipe 62 is equal to or less than the threshold value (No in Step S5), the process returns to Step S3 and continues to measure the pressure in the pipe 62 again. If the pressure value in the pipe 62 exceeds the threshold (step S5, Yes), the process proceeds to step S6. Therefore, the CPU 92b transmits an output signal to the signal unit 93 via the output circuit 92d.

  The signal unit 93 receives an output signal that the CPU 92b issues via the output circuit 92d. In response to receiving the output signal, the signal unit 93 transmits a signal that can be perceived by humans (step S6). Thereby, the signal part 93 can notify a human being that the pressure in the piping 62 has exceeded the threshold value. Therefore, the deterioration warning system of the seal unit 1 can suppress a situation in which the suction unit 20 stops in a state where the wear of the contact seal 4 has progressed.

  As a modification of step S6, when the pressure value in the pipe 62 exceeds the threshold value (step S5, Yes), the CPU 92b determines the environment of the drive device 8 and the internal space V via the output circuit 92d. An output signal for safely stopping the operation of at least one of the adjusting devices may be transmitted. Thereby, at least one of the drive device 8 and the device for adjusting the environment of the internal space V is safely stopped. The CPU 92b also transmits an output signal to the signal unit 93 via the output circuit 92d. The signal unit 93 transmits a signal that can be perceived by humans in response to reception of the output signal. Thereby, the signal part 93 can notify a human being that the pressure in the piping 62 exceeds a threshold value, and at least one of the apparatus which adjusts the environment of the drive device 8 and the internal space V is a stop state. Therefore, the deterioration warning system of the seal unit 1 can suppress a situation in which the suction unit 20 stops in a state where the wear of the contact seal 4 has progressed. And the semiconductor manufacturing apparatus 100 provided with the deterioration warning system of the seal unit 1 or the transfer device provided with the deterioration warning system of the seal unit 1 has a situation in which the suction unit 20 stops in a state in which the wear of the contact seal 4 has progressed. Can be suppressed.

[Modification]
FIG. 5 is an explanatory view showing a modification of the semiconductor manufacturing apparatus shown in FIG. FIG. 6 is an enlarged view of a cross section of the seal unit shown in FIG. 5 and 6, the same components as those described in FIGS. 1 and 3 are denoted by the same reference numerals, and the description thereof is omitted.

  The seal unit 1 according to the modification further includes an introduction groove 28 and an introduction path 7. The introduction groove 28 is an annular groove formed on the surface of the flange portion 21 on the radially outer side of the annular groove 25 and on the radially inner side of the suction groove 27. The introduction path 7 is a path for introducing gas into the introduction groove 28. The introduction path 7 is an opening that penetrates the housing 2 from the outside of the housing 2 and is connected to the introduction groove 28. Although there is one introduction groove 28 and one introduction path 7 according to the present embodiment, there may be a plurality of introduction grooves 28 and introduction paths 7.

  Further, in the flange portion 21, the introduction groove 28 is formed radially inward from the suction groove 27. Further, in the flange portion 21, the introduction groove 28 and the suction groove 27 are separated in the radial direction. For this reason, as shown in FIG. 6, a narrowed portion N <b> 2 is formed between the introduction groove 28 and the suction groove 27. The narrowed portion N2 is a gap having a height Δ3. Since the height Δ3 is sufficiently larger than the height Δ1, gas flows through the throttle portion N2.

  The introduction path 7 is provided with a flow rate adjustment unit that adjusts the flow rate of the gas. The flow rate adjustment unit is, for example, a flow rate adjustment valve installed in the introduction path 7. By adjusting the flow rate of the gas in the introduction path 7 by the flow rate adjustment unit, the gas flow in the introduction groove 28, the throttle portion N2, and the suction groove 27 can be appropriately controlled. Specifically, the amount of gas supplied to the introduction groove 28 is set to be as small as possible while ensuring a flow rate necessary for flowing foreign matter between the contact-type seal 4 and the non-contact-type seal 5 to the discharge path 6. It is preferable to do. It should be noted that the flow rate necessary for flowing foreign matter between the contact-type seal 4 and the non-contact-type seal 5 to the discharge path 6 is that the gas flow in the introduction groove 28, the throttle portion N2, and the suction groove 27 is a viscous flow. It is preferable that the flow rate be a certain level.

  In the seal unit 1 according to the modified example, the suction portion 20 sucks the gas in the suction groove 27 through the discharge path 6, so that the inside of the suction groove 27 becomes negative pressure. As a result, outside air is sucked into the introduction groove 28 via the introduction path 7. The outside air flowing into the introduction groove 28 passes through the throttle portion N2 and the suction groove 27 and is discharged to the outside of the housing 2 through the discharge path 6. As described above, the outside air flows through the introduction groove 28, the throttle portion N <b> 2, and the suction groove 27, whereby foreign matter generated due to wear of the contact seal 4 is discharged to the outside of the housing 2 through the discharge path 6. As a result, the foreign matter in the introduction groove 28 and the suction groove 27 is effectively recovered, so that the foreign matter is less likely to enter the internal space V through the non-contact type seal 5. When the height Δ3 is substantially the same as the depth of the suction groove 27 and the introduction groove 28, the outside air that has flowed into the introduction groove 28 may be guided to the discharge path 6 without reaching the surface of the flange portion 31. In this case, it is difficult to collect foreign matter near the surface of the flange portion 31. For this reason, the height Δ3 is preferably smaller than the depth of the suction groove 27 and the introduction groove 28 so that the outside air flowing into the introduction groove 28 is guided to the surface of the flange portion 31.

  In the seal unit 1 according to the modification, the gas introduced into the introduction groove 28 through the introduction path 7 is outside air. Further, the gas discharged from the discharge path 6 by the suction unit 20 is discharged as it is into the external space E. However, since a purification device (not shown) is disposed in the external space E, the outside air is introduced into the introduction groove 28 via the introduction path 7 after the foreign matter is collected. However, the present invention is not limited thereto, and a special gas such as nitrogen may be used as the gas introduced into the introduction groove 28. As the supply unit for introducing the special gas into the introduction groove 28, a known gas supply device can be arbitrarily adopted. In recent years, various gas supply apparatuses have been proposed.

  Further, in the seal unit 1 according to the modified example, the suction groove 27 is disposed on the non-contact seal 5 side with respect to the introduction groove 28. Therefore, the contact-type seal 4, the introduction groove 28, the suction groove 27 and the non-contact type seal 5 are arranged in the radial direction of the flange portion 21 in this order. Further, since the contact seal 4 is disposed on the high pressure side and the non-contact seal 5 is disposed on the low pressure side, the suction groove 27 is disposed on the low pressure side than the introduction groove 28. For this reason, the gas flow from the introduction groove 28 to the suction groove 27 is stabilized. Thereby, it is suppressed that a foreign material passes through the non-contact type seal 5 and enters the internal space V. However, the contact seal 4, the suction groove 27, the introduction groove 28 and the non-contact seal 5 may be arranged in the radial direction of the flange portion 21 in this order.

  Further, in the seal unit 1 according to the modification, the suction unit 20 is installed only on the discharge path 6 side, and gas is sucked. However, the present invention is not limited to this, and a supply unit that supplies gas to the introduction path 7 may be installed. For example, the supply unit is installed in a pipe connected to the introduction path 7 and feeds gas into the introduction path 7 at a predetermined flow rate. By doing so, foreign substances in the introduction groove 28 and the suction groove 27 can be collected more effectively by positively sending gas into the introduction groove 28. The supply unit and the suction unit 20 may have independent pumps, or may share one pump.

  Further, in the seal unit 1 according to the modification, only a pair of the introduction path 7 and the discharge path 6 are arranged between the contact seal 4 and the non-contact seal 5. Such an arrangement is preferable because the gas flow in the introduction groove 28, the throttle portion N2, and the suction groove 27 can be easily controlled. However, the present invention is not limited thereto, and a plurality of sets of introduction paths 7 and discharge paths 6 may be disposed between the contact seal 4 and the non-contact seal 5. By installing a plurality of sets of introduction paths 7 and discharge paths 6 in a multistage structure, entry of foreign matter into the internal space V is effectively suppressed.

  In the seal unit 1 according to the embodiment and the modification described above, the contact seal 4 and the non-contact seal 5 are arranged at different positions in the orthogonal direction with respect to the axis O. However, the contact-type seal 4 and the non-contact-type seal 5 may be arranged at different positions in the axis O direction. FIG. 7 is a view showing a seal unit when the contact-type seal and the non-contact-type seal are arranged at different positions in the axial direction. As shown in FIG. 7, the contact seal 4 and the non-contact seal 5 may seal a gap between the inner wall of the housing 2 and the outer periphery of the movable member 3.

  In FIG. 7, the movable member 3 may be a member that rotates about the axis O or a member that slides in the direction of the axis O. The housing 2 may have, for example, a bearing that rotatably supports the movable member 3 or a bearing that supports the movable member 3 so as to be linearly movable in the direction of the axis O. Further, the movable member 3 may be a member that can move only in the rotational direction or the axis O direction, or may be a member that can move in both the rotational direction and the axis O direction, for example.

  As described above, the deterioration warning system for the seal unit 1 is a deterioration warning system for the seal unit 1 that separates two spaces having different pressures. The seal unit 1 includes a housing 2 and a movable member 3 that passes through the housing 2 and is disposed with a gap between the housing 2. The seal unit 1 includes a contact-type seal 4 that seals the gap and a non-contact seal 5 that seals the gap at a position different from the contact-type seal 4. The seal unit 1 is connected to the suction groove 27 and discharges gas from the suction groove 27, which is a recess on the surface of the housing 2 at a position between the contact seal 4 and the non-contact seal 5. And a discharge path 6 serving as a passage. The deterioration warning system of the seal unit 1 includes a suction unit 20 that sucks the gas in the discharge path 6 and a control unit 92 that transmits a signal according to a change in pressure in the discharge path 6. The position where the non-contact type seal 5 is disposed is a position closer to the low pressure space of the two spaces than the position where the contact type seal 4 is disposed.

  When the wear of the contact seal 4 proceeds due to wear, the amount of gas passing through the contact seal 4 increases. For this reason, the gas flowing into the discharge path 6 connected to the gap at the position between the contact seal 4 and the non-contact seal 5 also increases, and the pressure in the discharge path 6 increases. The deterioration warning system of the seal unit 1 includes a control unit 92 that transmits a signal according to a change in pressure in the discharge path 6. Thereby, the deterioration warning system of the seal unit 1 can notify the person of the progress of wear of the contact-type seal 4 based on the change in the pressure in the discharge path 6. Therefore, the deterioration warning system of the seal unit 1 can suppress a situation in which the suction unit 20 stops in a state where the wear of the contact seal 4 has progressed.

  In the deterioration warning system of the seal unit 1, the control unit 92 includes a memory 92c that stores a threshold value and a CPU 92b that compares the pressure in the discharge path 6 with the threshold value. By doing in this way, the control part 92 compares the pressure in the discharge path 6 with a threshold value, and transmits a signal when the pressure in the discharge path 6 exceeds the threshold value. In addition, since the threshold value can be changed, the deterioration warning system for the seal unit 1 notifies the person of the progress of wear of the contact seal 4 according to the high airtightness required of the seal unit 1. Can be adjusted appropriately. Therefore, the deterioration warning system of the seal unit 1 can suppress a situation in which the suction unit 20 stops in a state where the wear of the contact seal 4 has progressed.

  In the deterioration warning system of the seal unit 1, the movable member 3 is a member that rotates around an axis O that is parallel to the direction passing through the housing 2, has a disk-shaped flange portion 31, and the flange portion 31 and the housing 2. It is preferable to arrange so as to provide a gap between them. By doing in this way, the clearance gap between the flange part 31 and the housing 2 turns into a clearance gap which has height in the axis | shaft O direction. Thereby, the gap between the flange part 31 and the housing 2 can improve the dimensional accuracy of the height as compared with the gap having a height in the direction orthogonal to the axis O. For this reason, the airtight performance of the non-contact type seal 5 that is a minute gap between the flange portion 31 and the housing 2 is improved. Therefore, since the deterioration warning system of the seal unit 1 can detect the progress of wear of the contact type seal 4 with higher accuracy, it is possible to suppress the situation where the suction unit 20 stops while the wear of the contact type seal 4 has progressed. .

  In the deterioration warning system of the seal unit 1, an introduction groove 28 that is a recess in the surface of the housing 2 located between the contact-type seal 4 and the non-contact-type seal 5, and a gas that is connected to the introduction groove 28 and flows into the introduction groove 28 It is preferable to provide an introduction path 7 that serves as a passage for introducing the. By doing so, the amount of gas flowing through the introduction groove 28 and the suction groove 27 increases. For this reason, even if foreign matter generated due to wear of the contact seal 4 enters between the contact seal 4 and the non-contact seal 5, the foreign matter is easily removed to the outside of the housing 2 through the discharge path 6. . As a result, the deterioration warning system of the seal unit 1 prevents the foreign matter from passing through the non-contact type seal 5 and entering the internal space V, while the wear of the contact type seal 4 has progressed. Can be stopped.

  In the deterioration warning system of the seal unit 1, the introduction groove 28 is preferably a recess in the surface of the housing 2 at a position between the contact seal 4 and the suction groove 27. In this way, the suction groove 27 is arranged on the lower pressure side than the introduction groove 28. For this reason, the gas flow from the introduction groove 28 to the suction groove 27 is stabilized. As a result, the deterioration warning system of the seal unit 1 prevents the foreign matter from passing through the non-contact type seal 5 and entering the internal space V, while the wear of the contact type seal 4 has progressed. Can be stopped.

DESCRIPTION OF SYMBOLS 1 Seal unit 2 Housing 3 Movable member 4 Contact-type seal 5 Non-contact-type seal 6 Discharge path 7 Introduction path 8 Drive device 9 Deterioration warning system 10 Housing 10e Opening part 12 Spacer 13 Bearing 14 Outer ring presser 15 Inner ring fixing nut 16 Between Seat 20 Suction part 21 Flange part 22 Bearing holding part 23 Recessed part 24 Notch part 25 Annular groove 26 Opening part 27 Suction groove 28 Introduction groove 31 Flange part 32 Table 33 Shaft part 61 Ventilation hole 62 Piping 81 Motor 82 Shaft 91 Pressure gauge 92 Control Unit 92a Input circuit 92b CPU
92c Memory 92d Output circuit 93 Signal unit 100 Semiconductor manufacturing device 211 Annular groove 212 O-ring C space E External space N1, N2 Narrowing part O-axis V Internal space

Claims (7)

A seal unit deterioration warning system that separates two spaces with different pressures,
A housing;
A movable member that passes through the housing and is disposed with a gap between the housing and the housing;
A contact-type seal that seals the gap;
A non-contact seal that seals the gap at a position different from the contact seal;
A suction groove that is a recess in the surface of the housing at a position between the contact seal and the non-contact seal;
A discharge path connected to the suction groove and serving as a path for discharging gas from the suction groove;
A suction part for sucking the gas in the discharge path;
A control unit for transmitting a signal according to a change in pressure in the discharge path,
The position at which the non-contact seal is disposed is a position closer to a low-pressure space of the two spaces than the position at which the contact seal is disposed.   The said control part has a memory | storage device which memorize | stores a threshold value, and the central processing unit which compares the pressure in the said discharge path with the said threshold value, The Claim 1 characterized by the above-mentioned. Deterioration warning system for the described seal unit.   The movable member is a member that rotates around a rotation axis parallel to a direction penetrating the housing, has a plate-like flange portion, and provides the gap between the flange portion and the housing. The deterioration warning system for a seal unit according to claim 1 or 2, wherein the deterioration warning system is provided. An introduction groove that is a recess in the surface of the housing at a position between the contact seal and the non-contact seal;
The deterioration warning of the seal unit according to any one of claims 1 to 3, further comprising an introduction path connected to the introduction groove and serving as a passage for introducing gas into the introduction groove. system.   5. The seal unit deterioration warning system according to claim 4, wherein the introduction groove is a recess in the surface of the housing located between the contact-type seal and the suction groove.   A conveying device comprising the seal unit deterioration warning system according to any one of claims 1 to 5.   A semiconductor manufacturing apparatus comprising the seal unit deterioration warning system according to any one of claims 1 to 5.

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