JP6565499B2 - SEAL STRUCTURE, ROTARY DRIVE DEVICE, CONVEYING DEVICE, MACHINE TOOL, AND SEMICONDUCTOR MANUFACTURING DEVICE - Google Patents

Description

  The present invention relates to a seal structure that separates two spaces having different pressures, a rotary-linear motion drive device, a transfer device, a machine tool, and a semiconductor manufacturing apparatus.

  In manufacturing equipment such as transfer equipment, semiconductor manufacturing equipment, or machine tools, the rotary stage is rotated and the semiconductor substrate, workpiece or tool is rotated or linearly moved while the process chamber such as a vacuum chamber is isolated from the external environment. A seal structure is used. As such a seal structure, for example, Patent Document 1 describes a seal device in which an oil seal attached to a housing is contracted in a radial direction and brought into surface contact with a roll shaft.

JP-A-10-009401

  Although the technique described in Patent Document 1 improves the sealing performance, since the oil seal is attached to the housing, for example, when the workpiece is heated in the process chamber, the heat of the workpiece is transmitted to the rotating shaft via the flat plate. In addition, the temperature of the contact-type seal also increases. Generally, an elastic member such as rubber or elastomer used for the seal has low thermal conductivity, and it is difficult to dissipate heat from the seal to the housing, so that the temperature around the seal is likely to rise. When the temperature of the contact-type seal rises, the contact-type seal expands thermally, and the contact pressure against the rotating shaft or the flat plate of the contact-type seal increases, so that the contact-type seal wears easily. For this reason, the life of the contact-type seal may be shortened, and the frequency of parts replacement may be increased.

  The present invention has been made in view of the above, and has a seal structure, a rotation-linear motion drive device, and a conveyance that can prevent the temperature of the rotary shaft and the contact-type seal from increasing and reduce the frequency of replacement of the contact-type seal. An object is to provide an apparatus, a machine tool, and a semiconductor manufacturing apparatus.

In order to achieve the above object, a seal structure according to the present invention is a seal structure that separates two spaces having different pressures, and
A cylindrical housing arranged in a space on the high-pressure side of the two spaces having different pressures, a shaft inserted into the housing, and an outer diameter surface of the shaft, and is rotated together with the shaft. An annular first seal member that moves a predetermined distance in a direction, contacts the housing, and seals a gap provided between the housing and the shaft, and an outer diameter surface of the shaft A fixed interval with the seal member, fixed at a position closer to the high-pressure side space than the first seal member, rotated with the shaft or moved a predetermined distance in the axial direction, and in contact with the housing; An annular second seal member for sealing the gap, and the housing is for cooling in a space surrounded by the first seal member and the second seal member in the gap. Characterized in that it comprises a plurality of through holes for passing the body.

Accordingly, the cooling fluid is caused to flow through the space between the first seal member and the second seal member through the through hole of the housing, so that the housing inner diameter surface, the outer diameter surface of the shaft, the first seal member, and the second seal member. Can be cooled.
In addition, the frictional heat between the first and second seal members and the housing, which is generated when the shaft rotates or moves in the axial direction, and the heat transmitted to the shaft due to the heating of the workpiece and the environment in the process chamber to the outside. By letting it escape, temperature rises of the shaft, the first seal member, and the second seal member can be suppressed. Therefore, the seal structure according to the present invention can reduce the replacement frequency of the first seal member and the second seal member which are contact seals.

As a desirable mode of the present invention, an interval between the first seal member and the second seal member is set larger than a distance in which the shaft, the first seal member, and the second seal member can move in the axial direction. With
The space-side openings of the plurality of through-holes include an axial movement end of the first seal member toward the space side on the high-pressure side and an axial direction of the second seal member toward the space side on the low-pressure side. Preferably, it is formed between the moving end.

As a result, the through hole can cause the cooling fluid to flow through the space in the entire movement range in the axial direction of the shaft.

  As a desirable mode of the present invention, the first seal member and the second seal member protrude radially inward of the shaft, are fixed to the shaft and one end of the shaft, and rotate together with the shaft. It is preferable to provide a seal flange portion that is sandwiched between and fixed.

  Thereby, when a shaft rotates with respect to a housing, relative rotation with respect to a shaft of a 1st seal member and a 2nd seal member is suppressed. That is, the first seal member and the second seal member are easy to rotate with the shaft. For this reason, the seal structure can reduce the possibility that the first seal member and the second seal member slide due to friction with the housing. Therefore, the seal structure can suppress the possibility of friction between the first seal member and the second seal member and the shaft.

  As a desirable mode of the present invention, the first seal member and the second seal member include a fixing portion that contacts the shaft, a lip portion that contacts the housing, and an annular connecting portion that connects the fixing portion and the lip portion. Are preferably provided.

  Accordingly, the first seal member and the second seal member are pressed against the housing by the elastic force generated by the elastic deformation of the lip portion. For this reason, the seal structure can increase the pressing force of the first seal member and the second seal member against the housing, and can improve the sealing performance of the gap. And since the part used as the heat bridge between a housing and a shaft is small compared with the case where a 1st seal member and a 2nd seal member are O rings etc., the frictional heat which arises between housings is shaft. It is difficult to conduct heat to the side. Thereby, the seal structure can further promote the radiation of frictional heat to the external space side. For this reason, the seal structure can suppress wear of the first seal member and the second seal member.

  As a preferred aspect of the present invention, the first seal member and the second seal member are provided in a space surrounded by the lip portion, the annular coupling portion, and the fixing portion, and the lip portion is provided in the housing. It is preferable to provide an urging member to be pressed.

  Accordingly, the first seal member and the second seal member are pressed against the housing by the elastic force due to the elastic deformation of the lip portion and the elastic force due to the elastic deformation of the biasing member. For this reason, the seal structure can increase the pressing force of the first seal member and the second seal member against the housing and improve the sealing performance of the gap. And even if abrasion arises in a lip | rip part, an urging member acts so that the pressing force of the 1st seal member and the 2nd seal member with respect to a housing may be maintained. For this reason, the seal structure can reduce the replacement frequency of the first seal member and the second seal member which are contact seals.

  As a desirable mode of the present invention, it is preferable that the rotary drive device includes the above-described seal structure in the housing and the electric motor that rotates the shaft in the second housing. With this structure, the rotary drive device can achieve high sealing performance and can reduce the frequency of replacement of contact-type seals.

  As a desirable aspect of the present invention, it is preferable that the transfer device includes the above-described seal structure and a movable member that moves the object to be conveyed, and the rotation and axial movement of the shaft are interlocked with the movable member. With this structure, the transport device can achieve high sealing performance and can reduce the frequency of replacement of the contact-type seal.

  As a desirable mode of the present invention, it is preferable that it is a machine tool provided with the seal structure mentioned above. With this structure, the machine tool can achieve high sealing performance and can reduce the frequency of replacement of the contact-type seal. As a result, the machine tool can improve the quality of the work.

  As a desirable aspect of the present invention, a semiconductor manufacturing apparatus having the above-described seal structure is preferable. With this structure, the semiconductor manufacturing apparatus can achieve high sealing performance and can reduce the frequency of replacement of the contact seal. As a result, the semiconductor manufacturing apparatus can improve the quality of the semiconductor that is the product.

  ADVANTAGE OF THE INVENTION According to this invention, the seal structure which can reduce the replacement frequency of a contact-type seal, a rotation-linear drive apparatus, a conveying apparatus, a machine tool, and a semiconductor manufacturing apparatus can be provided.

FIG. 1 is a cross-sectional view schematically showing a semiconductor manufacturing apparatus having a seal structure according to the first embodiment. FIG. 2 is a cross-sectional view schematically showing the seal structure according to the first embodiment. FIG. 3 is an enlarged view of a peripheral portion of the first seal member according to the first embodiment.

  Hereinafter, modes for carrying out the present invention (hereinafter referred to as embodiments) will be described 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.

(Embodiment 1)
FIG. 1 is a cross-sectional view schematically showing a semiconductor manufacturing apparatus having a seal structure according to the first embodiment. FIG. 2 is a cross-sectional view schematically showing the seal structure according to the first embodiment. 1 and 2 show a cross section of the seal structure 1 taken along a plane including the rotation center axis Zr of the rotation member 3 and parallel to the rotation center axis Zr. In the first embodiment, the axial direction is a direction parallel to the rotation center axis Zr, and the radial direction is a direction orthogonal to the rotation center axis Zr. FIG. 3 is an enlarged view of a peripheral portion of the first seal member according to the first embodiment. The seal structure 1 is a mechanical element that transmits rotation while keeping the internal space V sealed in a special environment such as a vacuum environment, a reduced pressure environment, or a process gas filling environment. The external space E separated from the internal space V is a space having a high pressure relative to the internal space V or an air atmosphere space. The seal structure 1 is applied to a manufacturing apparatus such as semiconductor manufacturing or machine tool manufacturing, a transport apparatus, and a rotary drive apparatus. Here, as an example, a case where the seal structure 1 is applied to a rotary drive device (spindle unit) having a spindle as a rotation shaft in a manufacturing apparatus for semiconductor manufacturing will be described. It is not limited.

  As shown in FIG. 1, for example, a semiconductor manufacturing apparatus 100 used for semiconductor manufacturing includes a seal structure 1, a housing 10, an electric motor 8, a linear motion mechanism 7, and a control that controls the electric motor 8 and the linear motion mechanism 7. Device 91 is included. The seal structure 1, the electric motor 8, and the linear motion mechanism 7, as the rotation-linear motion drive device 6, transmit the rotation of the electric motor 8 to rotate the movable member 33 as the transfer table, and the linear motion mechanism 7. The movement in the axial direction is transmitted to move the movable member 33 in the axial direction. The semiconductor manufacturing apparatus 100 moves an object to be transported (for example, a semiconductor substrate, a workpiece, or a tool) in the internal space V after making the internal space V of the housing 10 into a vacuum environment, a reduced pressure environment, and a process gas filling environment. It is mounted on the member 33 and moved. When moving the object to be transported, if the electric motor 8 and the linear motion mechanism 7 are installed in the internal space V, foreign matter may be generated by the operation of the electric motor 8 and the linear motion mechanism 7. Therefore, the semiconductor manufacturing apparatus 100 installs the electric motor 8 and the linear motion mechanism 7 in the external space E while leaving the movable member 33 in the internal space V. The seal structure 1 transmits the power of the electric motor 8 and the linear motion mechanism 7 installed in the external space E to the internal space V while improving the sealing performance by separating the internal space V and the external space E. The electric motor 8 is, for example, a direct drive motor, a drive device using a belt drive, a linear motor, a servo motor, or the like. The linear motion mechanism 7 is a drive device using, for example, a motor, a screw mechanism, and a linear motion guide mechanism. The control device 91 includes an input circuit, a central processing unit (CPU) that is a central processing unit, a memory that is a storage device, and an output circuit. According to the program stored in the memory, the electric motor 8 and the linear motion mechanism 7 are controlled, and the object to be transported (for example, a semiconductor substrate, workpiece or tool) in the internal space V is mounted on the transport table (movable member) 33. The semiconductor manufacturing apparatus 100 can manufacture a desired product.

The seal structure 1 includes a housing 2 and a rotating member 3. In the first embodiment, the housing 2 is formed of a metal such as aluminum alloy, iron, or stainless steel, for example, and has a through hole 22 that penetrates in the axial direction and a fluid passage (through hole) that penetrates in the radial direction. And a flange portion 21B formed in the middle in the axial direction of the cylindrical portion 21A.

  The flange portion 21B is a plate-shaped flange member. In the first embodiment, the shape of the flange portion 21B is circular in plan view, but these shapes are not limited to circular. The housing 2 is fixed to the housing 10 by fitting the flange portion 21B from the outside of the housing 10 so as to cover the opening 10e of the housing 10 and fastening the flange portion 21B and the wall surface of the housing 10 with a bolt 27. Has been. Thereby, the housing 2 can block the opening 10 e of the housing 10 from the outside of the housing 10. For this reason, the outer wall from one end of the housing 2 to the flange portion 21 </ b> B is exposed to the external space E. The flange portion 21B has an annular groove 21c in a portion overlapping the housing 10 in plan view, and the O-ring 11 is fitted in the annular groove. The O-ring 11 seals the gap between the flange portion 21 </ b> B and the housing 10 and improves the sealing performance of the seal structure 1.

  The rotating member 3 is made of, for example, a metal such as an aluminum alloy, iron, or stainless steel, and includes a shaft 81, a movable member 33, and a seal fixing member 35. The outer diameters of the shaft 81 and the seal fixing member 35 are smaller than the inner diameter of the through hole 22 of the housing, and the shaft 81 and the seal fixing member 35 are inserted into the through hole 22 of the housing 2. The seal fixing member 35 is fixed to one end of the shaft 81, and the movable member 33 is fixed to the end of the seal fixing member 35. In the first embodiment, the shaft 81 and the seal fixing member 35 and the seal fixing member and the movable member 33 are fixed by screws formed respectively. The other end of the shaft 81 is connected to the output shaft 81 of the electric motor 8. In the first embodiment, the shaft 81 is formed integrally with the output shaft of the electric motor 8, but a coupling may be interposed between the shaft 81 and the output shaft of the electric motor 8.

  The movable member 33 rotates together with the shaft 81 and the seal fixing member 35. The movable member 33 has a cylindrical body portion 331 that is in contact with one end portion of the seal fixing member 35 and a mounting portion 332 that is provided at one end portion of the body portion 331 opposite to the seal fixing member shaft 81 side. The outer diameter of the body portion 331 is smaller than the inner diameter of the through hole 22 of the housing, like the shaft 81. In the first embodiment, the placement portion 332 is a plate-like member formed integrally with the body portion 331 and has a circular shape in plan view. The outer diameter of the mounting portion 332 is larger than the outer diameter of the body portion 331. The object to be transported is placed on the surface of the placement portion 332 opposite to the body portion 331 side. In addition, the trunk | drum 331 and the mounting part 332 may be comprised by another member.

  In the above-described embodiment, the movable member 33 rotates by the electric motor 8 and linearly moves in the axial direction by the linear motion mechanism 7. However, the operation of the movable member 33 is not necessarily one of the rotational motion and the linear motion. There is no need. For example, the linear motion 7 may be linearly moved while the movable member 33 is rotated by the electric motor 8.

  A seal fixing portion 32 is formed at one end of the shaft 81. The seal fixing portion 32 has a seal fixing recess 32b that is an annular notch centered on the rotation center axis Zr. Similarly, a seal fixing portion 36 is formed at one end of the seal fixing member 35. The seal fixing portion 36 has a seal fixing recess 36b that is an annular notch centered on the rotation center axis Zr.

  As shown in FIG. 2, in this embodiment, the shaft 81 and the seal fixing member 35 are connected to each other by a screw portion 81 a formed at one end of the shaft 81 and a screw hole 35 a formed at one end of the seal fixing member 35. Although fixed, the method of fixing the shaft 81 and the seal fixing member 35 is not limited to this. For example, a screw hole may be formed in the shaft 81, a through hole may be formed in the seal fixing member 35, and both may be fastened and fixed by one or a plurality of bolts. Similarly, the seal fixing member 35 and the movable member 33 are fixed to each other by a screw portion 35 b formed at the other end of the seal fixing member 35 and a screw hole 331 a formed in the body portion 331 of the movable member 33. However, the method of fixing the seal fixing member 35 and the movable member 33 is not limited to this. For example, a screw hole may be formed in the other end surface of the seal fixing member 35 and a through hole may be formed in the movable member 33, and both may be fastened and fixed by one or a plurality of bolts.

The seal fixing portion 36 of the seal fixing member 35 is provided with a first seal member 5A, and the seal fixing portion 32 of the shaft 81 is provided with a second seal member 5B. The first seal member 5A and the second seal member 5B are made of a non-metallic material such as resin or rubber, for example. The first seal member 5A and the second seal member 5B are annular elastic members centered on the rotation center axis Zr, and are formed in the seal fixing recess 36b of the seal fixing member 35 so as to contact the inner diameter surface of the through hole 22 of the housing. In the first seal member 5A, the second seal member 5B is fitted in the seal fixing recess 32b of the shaft 81, and the seal fixing portion 36 of the seal fixing member 35 and the end surface of the trunk portion 331 of the movable member 33 are first. The seal member 5 </ b> A is fixed by sandwiching the second seal member 5 </ b> B between the seal fixing portion 32 of the shaft 81 and the end surface of the seal fixing member 35. Accordingly, the first seal member 5A and the second seal member 5B rotate around the rotation center axis Zr together with the shaft 81, the seal fixing member 35, and the movable member 33. The first seal member 5 </ b> A and the second seal member 5 </ b> B seal the first gap 15 between the outer diameter surface 82 b of the shaft 81 and the through hole 22 of the housing 2.

  As shown in FIG. 3, the first seal member 5A and the second seal member 5B are elastic members, and each includes a lip portion 51A, 51B, a fixed portion 52A, 52B, an annular coupling portion 53A, 53B, and a seal. Flange portions 54A and 54B. The lip portions 51 </ b> A and 51 </ b> B are annular members along the inner wall of the through hole 22 included in the housing 2, and are in contact with the inner wall of the through hole 22. The fixing portion 52 </ b> A of the first seal member 5 </ b> A is an annular member along the outer diameter surface 35 b of the seal fixing member 35 and is in contact with the outer diameter surface 35 b of the seal fixing member 35. The fixing portion 52B of the second seal member 5B is an annular member along the outer diameter surface 82b of the shaft 81 and is in contact with the outer diameter surface 82b of the shaft 81. The annular connecting portions 53A and 53B connect the lip portions 51A and 51B and the fixing portions 52A and 52B. With this structure, the cross-sectional shape including the lip portions 51A and 51B, the fixing portions 52A and 52B, and the annular coupling portions 53A and 53B is substantially U-shaped. Thereby, the pressing force of the first seal member 5A and the second seal member 5B against the housing 2 is increased by the pressure due to the elastic deformation of the lip portions 51A and 51B. For this reason, the sealing performance of the first gap 15 is improved.

  The seal flange portions 54A and 54B are members that protrude radially inward from the fixed portions 52A and 52B. The seal flange portions 54A and 54B are, for example, annular and plate-like members, and are inserted into the seal fixing recesses 32b and 36b of the seal fixing portions 32 and 36, respectively. When the movable member 33 is fixed to the seal fixing member 35, the movable member 33 sandwiches and fixes the seal flange portion 54A of the first seal member 5A inserted into the seal fixing recess 36b of the seal fixing member 35. Further, when the seal fixing member 35 is fixed to the shaft 81, the shaft 81 and the seal fixing member 35 sandwich and fix the seal flange portion 54B of the second seal member 5B inserted into the seal fixing recess 36b of the shaft 81. Thereby, relative rotation with respect to the rotation member 3 of 5 A of 1st seal members and the 2nd seal member 5B is suppressed. That is, the first seal member 5 </ b> A and the second seal member 5 </ b> B are easily rotated together with the rotating member 3. For this reason, the seal structure 1 can reduce the possibility that the first seal member 5 </ b> A and the second seal member 5 </ b> B slide against the rotating member 3 due to friction with the housing 2. Therefore, the seal structure 1 can suppress the possibility of friction between the first seal member 5 </ b> A and the second seal member 5 </ b> B and the rotating member 3.

  In the first embodiment, the movable member 33 is integrally formed with a placing portion 332 having a function of a transfer table and a body portion 331 having a function of a seal presser for sandwiching the first seal member 5A. With this structure, the seal structure 1 can reduce the number of parts and suppress the manufacturing cost. In addition, the placing part 332 and the trunk part 331 may be separate members.

  As shown in FIG. 3, urging members 56A and 56B are arranged in a space surrounded by the lip portions 51A and 51B, the annular coupling portions 53A and 53B, and the fixing portions 52A and 52B. The urging members 56A and 56B are made of, for example, stainless steel, and are elastic plates having a V shape in cross-section when the plate-like plate-like portions 561a and 561b and the plate-like portions 561a and 561b are bent at the bent portions 562a and 562b. Is the body. In the urging members 56A and 56B, an elastic force is generated so that the tips on the groove side of the plate-like portions 561a and 561b spread. Thereby, the urging members 56 </ b> A and 56 </ b> B can press the lip portions 51 </ b> A and 51 </ b> B against the through hole 22 of the housing 2.

  The first seal member 5A and the second seal member 5B are pressed against the through hole 22 by the pressure due to the elastic deformation of the lip portions 51A and 51B and the pressure due to the elastic deformation of the urging members 56A and 56B. For this reason, the seal structure 1 can increase the pressing force of the first seal member 5 </ b> A and the second seal member 5 </ b> B against the through hole 22.

  As shown in FIG. 3, the tip portions 511 a and 511 b are in contact with the through hole 22 in the lip portions 51 </ b> A and 51 </ b> B of the first seal member 5 </ b> A and the second seal member 5 </ b> B. On the other hand, the base portions 512 a and 512 b of the lip portions 51 </ b> A and 51 </ b> B are not in contact with the through hole 22 and are opposed to the through hole 22 with a gap. Thereby, since the 1st seal member 5A and the 2nd seal member 5B contact the through-hole 22 linearly in the front-end | tip parts 511a and 511b of lip | rip parts 51A and 51B, it can improve sealing performance.

Further, the housing 2 is provided with fluid passages 23 and 23 for allowing the cooling fluid to pass through the cooling space M surrounded by the first seal member 5A and the second seal member 5B . Thereby, the inner peripheral surface (inner wall ) of the housing 2 touching the cooling space M, the outer peripheral surface of the seal fixing member 35, the first seal member 5A, and the second seal member 5B can be cooled.

The fluid passages 23 and 23 are formed at an intermediate position in the axial direction of the cylindrical portion 21 </ b> A of the housing 2. An annular groove 22a is formed on the inner wall of the through hole 22 of the cylindrical portion 21A, the fluid passage 23 is open to the bottom of the annular groove 22a. The fluid passage 23 and the annular groove 22a are formed in such a position that they are always located between the first seal member 5A and the second seal member 5B in the range of the axial movement of the shaft 81 with respect to the housing 2. Further, it is desirable that the distance between the first seal member 5A and the second seal member 5B be larger than a value obtained by adding the axial stroke of the rotating member 3 and the axial width dimension of the annular groove 22a. . If the distance between the first seal member 5A and the second seal member 5B is smaller than the axial stroke of the rotary member 3, the first seal member 5A and the second seal member 5B are moved when the rotary member 3 moves in the axial direction. Since either one may pass through the annular groove 22a, it is not preferable.

In the first embodiment, when the shaft 81 rotates, friction occurs between the first seal member 5 </ b> A and the second seal member 5 </ b> B, which are contact seals, and the through hole 22 of the housing 2. Since the first seal member 5A and the second seal member 5B are made of resin or rubber as described above, the thermal conductivity of the first seal member 5A and the second seal member 5B is other than that made of metal. It is about 1/1000 to 1/100 compared with the member. Therefore, most of the frictional heat generated between the first seal member 5A, the second seal member 5B and the through hole 22 is transmitted to the through hole 22 side, and the temperature rise of the rotating member 3 is suppressed. Since a gap is provided between the movable member 33 and the through hole 22 so as to connect to the internal space V that is a high vacuum environment, the heat of the through hole 22 in the first embodiment is difficult to transfer to the movable member 33 side. It has become. On the other hand, the heat of the through hole 22 is transferred from the flange portion 21B to the cylindrical portion 21A. In the cooling space M and the external space E, unlike the internal space V which is a high vacuum environment, there is convection of air, so heat transfer is likely to occur between the air in the external space E and the outer surface of the outer member 21. Thus, the heat radiation of the heat generated on the inner wall of the through hole of the housing 2 is accelerated by the friction between the first seal member 5A and the second seal member 5B. For this reason, since the temperature rise of 5 A of 1st seal members and the 2nd seal member 5B is suppressed, the thermal expansion of 5 A of 1st seal members and the 2nd seal member 5B is suppressed. Accordingly, the increase in the contact pressure of the first seal member 5A and the second seal member 5B with respect to the through hole 22 is suppressed, so that the progress of wear of the first seal member 5A and the second seal member 5B is suppressed.
Therefore, the seal structure 1 can reduce the replacement frequency of the first seal member 5A and the second seal member 5B which are contact seals.

In the seal structure 1, since the rotary member 3 rotates with respect to the housing 2 and moves in the axial direction, the axial length of the sliding contact surface of the through hole 22 of the housing 2 with the first seal member 5A. This is made larger than the axial stroke of the rotating member 3 with respect to the housing 2. Similarly, the axial length of the sliding contact surface of the through hole 22 with the second seal member 5 </ b> B is also made larger than the axial stroke of the rotating member 3 with respect to the housing 2. Thereby, the internal space V can be sealed with respect to the external space E by the first seal member 5 </ b> A in the entire region where the rotating member 3 moves in the axial direction by a predetermined distance.

  As described above, the first seal member 5A (second seal member 5B) includes the lip portion 51A (51B), the fixing portion 52A (52B), and the annular coupling portion 53A (53B). Thereby, since the part used as the heat bridge between the through-hole 22 and the rotation member 3 is small compared with the case where it is an O-ring etc., for example, the 1st seal member 5A and the 2nd seal member 5B are through-holes. The frictional heat generated between the two members 22 is difficult to conduct to the rotating member 3 side. Further, the housing 2, the rotary member 3, the first seal member 5A, and the second seal member 5B are cooled by flowing a cooling fluid in the space between the first seal member 5A and the second seal member 5B. . Thereby, the seal structure 1 can further promote the radiation of the frictional heat to the outside. For this reason, the seal structure 1 can suppress wear of the first seal member 5A and the second seal member 5B.

  In the first embodiment, the urging members 56A and 56B act to maintain the contact pressure even if the lip portions 51A and 51B are worn. For this reason, the seal structure 1 can reduce the replacement frequency of the first seal member 5A and the second seal member 5B, which are contact seals.

  The material of the first seal member 5A and the second seal member 5B is more preferably polyethylene or polytetrafluoroethylene. Polyethylene or polytetrafluoroethylene is excellent in wear resistance and chemical resistance as a material of the first seal member 5A and the second seal member 5B, and is suitable for lubrication with the through hole 22 of the housing 2.

  The material of the shaft 81, the seal fixing member 35, and the through hole 22 of the housing 2 with which the first seal member 5A and the second seal member 5B are in contact is high carbon chromium bearing steel, martensitic stainless steel, precipitation hardening stainless steel. Any one of steel and a high silicon alloy of precipitation hardening stainless steel containing 3.4 mass% or more of Si is preferable. With this structure, the wear of the first seal member 5A and the second seal member 5B is suppressed, and in the first embodiment, the seal structure 1 has a replacement frequency of the first seal member 5A and the second seal member 5B that are contact-type seals. Can be reduced.

Although the first embodiment has been described above, the present invention is not limited to the contents described above. In addition, at least one of various omissions, replacements, and changes of the components can be made without departing from the gist of the first embodiment.
For example, in the above-described first embodiment, the second seal member 5 B, although using the same as the first sealing member 5 A, if the same structure, shape and size may differ . For example, the shaft 81, increasing the outer diameter of the rotating member 3, or less formed, be used accordingly large relative to the first sealing member 5 A or less second seal member 5 B .

DESCRIPTION OF SYMBOLS 1 Seal structure 10 Housing | casing 11 O-ring 15 1st clearance 2 Housing 21A Cylindrical part 21B flange part 22 Through-hole 22a Annular groove 23 Through-hole 3 Rotating member 32 Seal fixing | fixed part 32b Seal fixing recessed part 33 Movable member (conveying table, seal Presser member)
331 body portion 332 mounting portion 35 seal fixing member 36 seal fixing portion 36b seal fixing recess 5A first seal member 5B second seal member 51A, 51B lip portion 52A, 52B fixing portion 53A, 53B annular connecting portion 54A, 54B seal flange Part 56A, 56B Energizing member 6 Rotation-linear motion drive device 7 Linear motion mechanism 8 Electric motor 91 Control device 100 Semiconductor manufacturing device E External space V Internal space M Cooling space

Claims (11)

  A seal structure that separates two spaces having different pressures, a cylindrical housing disposed in a space on the high-pressure side of the two spaces having different pressures, a shaft inserted into the housing, and fixed to the shaft An annular first seal member that rotates or moves axially together with the shaft, contacts the housing, and seals a gap provided between the housing and the shaft, and an outer diameter surface of the shaft The housing is fixed at a position closer to the high-pressure side space than the first seal member and has a predetermined distance from the first seal member, and rotates or moves axially with the shaft for a predetermined distance. And an annular second seal member that seals the gap, and the housing includes the first seal member and the second seal member within the gap. Seal structure, characterized in that it comprises a plurality of through holes for passing the cooling fluid in a space surrounded by.   The first seal member and the second seal member protrude radially inward of the shaft, are fixed to the shaft and one end of the shaft, and are sandwiched and fixed by a rotating member that rotates with the shaft. The seal structure according to claim 1, further comprising a seal flange portion. The first seal member and the second seal member include a fixing part that contacts the shaft, a lip part that contacts the housing, and an annular connection part that connects the fixing part and the lip part. The seal structure according to claim 1 or 2.   The first seal member and the second seal member are provided in a space surrounded by the lip portion, the annular coupling portion, and the fixing portion, and include a biasing member that presses the lip portion against the housing. The seal structure according to claim 3.   The space surrounded by the lip portion, the annular connecting portion, and the fixing portion of the first seal member and the second seal member faces the high-pressure side space of the two spaces having different pressures. The seal structure according to claim 3 or 4, wherein the seal structure is open. An axial interval between the first seal member and the second seal member is set to be larger than a distance in which the shaft, the first seal member, and the second seal member can move in the axial direction. The seal structure according to any one of claims 1 to 5 . 2. The seal structure according to claim 1 , wherein the through hole has an axial opening position on the space side between the first seal member and the second seal member.   A rotation drive device comprising the seal structure according to claim 1 and an electric motor that rotates the shaft.   A transport apparatus comprising: the seal structure according to claim 1; and a movable member that moves an object to be transported, wherein the rotation of the shaft is interlocked with the movable member.   A machine tool comprising the seal structure according to any one of claims 1 to 7.   A semiconductor manufacturing apparatus comprising the seal structure according to claim 1.

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