JP2014134238A - Rolling mechanism, transport device, and semiconductor manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rolling mechanism capable of suppressing burst of a magnetic fluid seal.SOLUTION: A rolling mechanism 1 includes a housing 2, a shaft 3 inserted into the housing 2, a bearing 4 provided in the housing 2 and rotatably supporting the shaft 3, a magnetic fluid seal 6 sealing a first clearance on an outer periphery of the shaft 3, and a labyrinth seal 7 sealing a second clearance on the outer periphery of the shaft 3. The labyrinth seal 7 has a clearance 71 with a predetermined width W1 in an axial direction of the shaft 3.

Description

  The present invention relates to a rotation mechanism, a transport apparatus, and a semiconductor manufacturing apparatus, and more particularly to a rotation mechanism, a transport apparatus, and a semiconductor manufacturing apparatus that can suppress burst of a magnetic fluid seal.

  In recent rotation mechanisms used in conveying apparatuses and semiconductor manufacturing apparatuses, a magnetic fluid seal is employed as a seal member for sealing the clearance on the outer periphery of the shaft. In such a configuration, there is a problem that the burst reduction of the magnetic fluid seal should be suppressed. The burst phenomenon is a phenomenon in which, for example, when the pressure in a region where a plurality of stages of magnetic fluids are arranged fluctuates rapidly, the magnetic fluid film is broken and the magnetic fluid is scattered. As conventional rotation mechanisms related to such problems, techniques described in Patent Documents 1 to 5 are known.

Japanese Patent Laid-Open No. 5-288277 JP-A-6-257675 Japanese Patent Laid-Open No. 11-037304 JP 2000-205418 A Japanese Patent Laid-Open No. 2000-220751

  It is an object of the present invention to provide a rotation mechanism, a transport device, and a semiconductor manufacturing apparatus that can suppress a burst of a magnetic fluid seal.

  In order to achieve the above object, a rotating mechanism according to the present invention includes a housing, a shaft inserted through the housing, a bearing that is installed in the housing and rotatably supports the shaft, and an outer periphery of the shaft. A magnetic fluid seal for sealing one clearance and a labyrinth seal for sealing a second clearance on the outer periphery of the shaft, and the labyrinth seal has a gap having a predetermined width in the axial direction of the shaft. It is characterized by that.

  In addition, the transport device includes the rotation mechanism described above.

  In addition, this semiconductor manufacturing apparatus includes the rotation mechanism described above.

  In the rotating mechanism according to the present invention, when the shaft rotates, the first gap functions as a labyrinth seal and suppresses the gas flow between the clearance on the outer periphery of the shaft and the first chamber. At this time, the pressure in the section from the labyrinth seal to the magnetic fluid seal changes with a delay with respect to the pressure change in the first chamber on the labyrinth seal side. Thereby, the pressure change of the said area is relieve | moderated and there exists an advantage by which the burst of a magnetic fluid seal | sticker is suppressed.

FIG. 1 is a configuration diagram showing a rotation mechanism according to an embodiment of the present invention. FIG. 2 is an enlarged view showing a labyrinth seal of the rotation mechanism described in FIG. 1. FIG. 3 is an explanatory view showing a modified example of the labyrinth seal shown in FIG. 2. FIG. 4 is an explanatory view showing a modified example of the labyrinth seal shown in FIG. FIG. 5 is an explanatory view showing a modification of the rotation mechanism shown in FIG. FIG. 6 is an explanatory view showing a modification of the rotation mechanism shown in FIG.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments. Further, the constituent elements of this embodiment include those that can be replaced while maintaining the identity of the invention and that are obvious for replacement. In addition, a plurality of modifications described in this embodiment can be arbitrarily combined within a range obvious to those skilled in the art.

[Rotation mechanism]
FIG. 1 is a configuration diagram showing a rotation mechanism according to an embodiment of the present invention. The figure shows an axial sectional view of the rotating mechanism 1 attached to the partition wall 100. In addition, an alternate long and short dash line O in the figure indicates the rotation axis of the rotation mechanism 1.

  The rotation mechanism 1 is a mechanical element that transmits rotation, and is applied to, for example, a transfer device, a semiconductor manufacturing device, a flat panel display manufacturing device, and the like used in a special environment such as a vacuum chamber. Here, as an example, a description will be given of a case where the rotation mechanism 1 is a rotation introduction machine of a spindle unit including a spindle as a rotation shaft and is installed in a partition wall 100 that partitions the first chamber 110 and the second chamber 120 ( (See FIG. 1).

  The rotating mechanism 1 includes a housing 2, a shaft 3, and a bearing 4.

  The housing 2 is a member that accommodates the bearing 4. The shaft 3 is an output shaft of the rotation mechanism 1 and is inserted into the housing 2 and penetrates the housing 2. The bearing 4 is installed in the housing 2 and rotatably supports the shaft 3.

  For example, in the configuration of FIG. 1, the housing 2 has a cylindrical shape as a whole, and has a flange portion 21 for attachment at one end portion. Further, the housing 2 is inserted into the opening 101 of the partition wall 100 from the second chamber 120 side, and is fixed to the wall surface of the partition wall 100 by bolt fastening while the flange portion 21 is locked to the edge of the opening portion 101 of the partition wall 100. Yes. As a result, the housing 2 is disposed so as to close the opening 101 of the partition wall 100 from the second chamber 120 side. Further, the flange portion 21 has a circumferential groove 211 on an engagement surface with the partition wall 100, and an O-ring 212 is disposed in the circumferential groove 211. Thereby, the clearance gap between the flange part 21 and the wall surface of the partition 100 is sealed, and airtightness is ensured. Further, the housing 2 has a stepped inner peripheral surface shape composed of a small diameter portion 22 and a large diameter portion 23, and the small diameter portion 22 is arranged toward the first chamber 110 side.

  The shaft 3 has a stepped shape and is inserted into the hollow portion of the housing 2 so as to penetrate the housing 2 in the axial direction. The shaft 3 includes a shaft main body 31 and an output flange 32, and the output flange 32 is attached to the end of the shaft main body 31 on the first chamber 110 side by bolt fastening. For example, the output flange 32 is connected to a drive shaft of a transfer device or a semiconductor manufacturing device. Further, a power device (not shown) such as a belt drive device, a servo motor, and a direct drive motor is connected to the end of the shaft 3 on the second chamber 120 side.

  The bearing 4 is a ball bearing and is disposed inside the housing 2. Moreover, a pair of bearings 4 and 4 are arrange | positioned adjacent to the axial direction of the shaft 3, and are supporting the shaft 3 rotatably. Further, the outer ring 41 of each bearing 4, 4 is fitted and fixed to the small diameter portion 22 of the housing 2. Further, the outer ring 41 of the bearing 4 on the second chamber 120 side is positioned in the axial direction of the shaft 3 by coming into contact with the step portion between the small diameter portion 22 and the large diameter portion 23 of the housing 2. Further, the inner rings 42 of the bearings 4 and 4 are fitted and fixed to the shaft 3. Further, the inner ring 42 of the bearing 4 on the second chamber 120 side is positioned in the axial direction of the shaft 3 by contacting the stepped portion of the shaft 3.

  Further, the outer ring 41 of the bearing 4 on the first chamber 110 side is held by an outer ring presser 51. The outer ring retainer 51 is a member that retains the outer ring 41 of the bearing 4 from the axial direction of the shaft 3. In the configuration of FIG. 1, the outer ring presser 51 is an annular member that matches the diameter of the outer ring 41 of the bearing 4, and holds the outer ring 41 in contact with the axial end surface of the outer ring 41 from the first chamber 110 side. Moreover, the housing 2 has the spigot part 24 in the edge part by the side of the 1st chamber 110, and the outer ring | wheel holder 51 is inserted in this spigot part 24, and is being fixed by bolt fastening. Further, the inlay portion 24 has a circumferential groove 241 on a fitting surface with the outer ring presser 51, and an O-ring 242 is disposed in the circumferential groove 241. Thereby, the clearance gap between the inlay part 24 and the outer ring | wheel holder | retainer 51 is sealed, and airtightness is ensured.

  A spacer 52 is disposed between the inner ring 42 of the bearing 4 on the first chamber 110 side and the output flange 32 of the shaft 3. The spacer 52 is a member that adjusts the gap between the inner ring 42 and the output flange 32, and is interposed between the inner ring 42 and the output flange 32 to close the gap. For example, in the configuration of FIG. 1, the spacer 52 is made of an annular member, is fitted on the outer periphery of the shaft body 31, and is sandwiched between the inner ring 42 and the output flange 32. A spacer 52 holds the inner ring 42 of the bearing 4 from the axial direction of the shaft 3. Therefore, the spacer 52 also serves as an inner ring presser that holds the inner ring 42 of the bearing 4.

  In this rotating mechanism 1, the driving force from a power unit (not shown) is transmitted through the shaft 3, and the output flange 32 rotates. Further, when the power unit adjusts the input of the driving force to the shaft 3, the rotational speed and the rotational direction of the output flange 32 are freely controlled. Thereby, the rotation mechanism 1 functions as a rotation introducer.

[Seal structure]
In the configuration of FIG. 1, the first chamber 110 and the second chamber 120 are partitioned through the partition wall 100 as described above. Further, the first chamber 110 and the second chamber 120 have different atmospheres. For example, in the semiconductor manufacturing apparatus, a special environment (for example, a reduced pressure environment, a vacuum environment, a process gas filling environment, etc.) is formed in the first chamber 110, and outside air is introduced into the second chamber 120.

  For this reason, in the configuration of FIG. 1, the rotation mechanism 1 includes the following seal structure in order to partition the first chamber 110 and the second chamber 120.

  First, as described above, the O-ring 212 is disposed on the joint surface between the flange portion 21 of the housing 2 and the partition wall 100 to seal these gaps. An O-ring 242 is disposed on the fitting surface between the outer ring presser 51 and the inlay portion 24 of the housing 2 to seal these gaps.

  The rotation mechanism 1 includes a magnetic fluid seal 6. The magnetic fluid seal 6 is a seal member that seals the clearance on the outer periphery of the shaft 3, and a known member can be adopted. For example, in the configuration of FIG. 1, the magnetic fluid seal 6 is disposed in the clearance (first clearance) between the inner peripheral surface of the opening on the second chamber 120 side of the housing 2 and the shaft 3. A magnetic fluid seal 6 is held on the housing 2 via a retaining ring or the like. Thereby, the opening part by the side of the 2nd chamber 120 of the housing 2 is sealed. In addition, since the magnetic fluid seal 6 has a limited pressure difference that can be sealed alone, it is used in a plurality of stages. Thereby, the pressure change in the arrangement | positioning area | region of the magnetic fluid seal 6 becomes loose, and a high sealing performance is obtained.

  Here, in the structure provided with a general magnetic fluid seal, there is a problem that the burst phenomenon of the magnetic fluid seal should be suppressed. The burst phenomenon is a phenomenon in which, for example, when the pressure in a region where a plurality of stages of magnetic fluids are arranged fluctuates rapidly, the magnetic fluid film is broken and the magnetic fluid is scattered.

  For this reason, in the configuration of FIG. 1, the rotating mechanism 1 includes a labyrinth seal 7 (71) in order to suppress the burst phenomenon of the magnetic fluid seal.

  FIG. 2 is an enlarged view showing a labyrinth seal of the rotation mechanism described in FIG. 1.

  The labyrinth seal 7 is a seal that seals the clearance on the outer periphery of the shaft 3, and is disposed at a position different from the magnetic fluid seal 6. For example, in the configuration of FIG. 1, the labyrinth seal 7 is formed in a region from the bearing 4 on the first chamber 110 side to the output flange 32 of the shaft 3. Specifically, the labyrinth seal 7, the pair of bearings 4, 4, and the magnetic fluid seal 6 are arranged in the axial direction of the shaft 3 from the first chamber 110 toward the second chamber 120. Thereby, the clearance (second clearance) of the outer periphery of the shaft 3 in the opening on the first chamber 110 side of the housing 2 is sealed.

  Further, as shown in FIG. 2, the labyrinth seal 7 has a first gap 71 having a predetermined width W1. The width W <b> 1 of the gap 71 is a width for realizing the sealing function of the labyrinth seal 7 and is measured as the axial width of the shaft 3. The width W1 is preferably in the range of 5 [μm] ≦ W1 ≦ 30 [μm], and more preferably in the range of 5 [μm] ≦ W1 ≦ 15 [μm].

  Further, in the configuration of FIG. 2, a second gap 72 and a third gap 73 having predetermined widths W2 and W3 are provided in an auxiliary manner. These gaps 72 and 73 are gaps for accurately positioning the outer ring presser 51 and the output flange 32 of the shaft 3 in the axial direction. By the gaps 72 and 73, the width W1 of the first gap 71 is ensured with high accuracy. The widths W2 and W3 of the gaps 72 and 73 can be arbitrarily set within a range obvious to those skilled in the art, but are set to a range of about 0.1 [mm] to 0.2 [mm], for example. It is preferable.

  The first gap 71 is formed between the output flange 32 of the shaft 3 that is a rotating system and the outer ring presser 51 that is a stationary system, and constitutes the labyrinth seal 7. For example, in the configuration of FIG. 2, the end face of the output flange 32 and the end face of the outer ring retainer 51 are planes perpendicular to the rotation axis O of the shaft 3 and are disposed to face each other across the width W1. Thereby, an annular gap 71 surrounding the outer periphery of the shaft 3 and the spacer 52 is formed. Further, the gap 71 communicates with the clearance between the spacer 52 and the outer ring presser 51 on the radially inner side, and communicates with the first chamber 110 on the radially outer side.

  In the configuration of FIG. 2, the width W <b> 1 of the gap 71 is defined by the step G between the end surface of the outer ring 41 of the bearing 4 and the end surface of the inner ring 42. Specifically, the end surface of the outer ring 41 and the end surface of the inner ring 42 are arranged with a step G in the axial direction of the shaft 3. The axial gauge of the outer ring retainer 51 that contacts the end surface of the outer ring 41 and the axial gauge of the spacer 52 that contacts the end surface of the inner ring 42 are set to be substantially equal. The spacer 52 is sandwiched and disposed between the end face of the output flange 32 and the end face of the inner ring 42, whereby the distance between the end face of the output flange 32 and the end face of the outer ring retainer 51 (width W1 of the gap 71). Is properly secured.

  The second gap 72 (auxiliary gap) is formed in a fitting portion between the outer ring presser 51 and the spigot portion 24 of the housing 2. For example, in the configuration of FIG. 2, the end surface in the axial direction of the outer ring retainer 51 and the end surface in the axial direction of the inlay portion 24 are planes perpendicular to the rotation axis O of the shaft 3. In the region up to the position where the O-ring 242 is disposed, the O-rings 242 are disposed so as to face each other with a width W2. Further, an annular gap 72 surrounding the outer periphery of the shaft 3 and the bearing 4 is formed. Further, the gap 72 communicates with the clearance on the outer periphery of the shaft 3 on the radially inner side and is sealed with the O-ring 242 on the radially outer side.

  In the configuration of FIG. 2, the second gap 72 is defined by the positional relationship between the end surface of the spigot part 24 and the end surface of the outer ring 41 of the bearing 4. Specifically, the end surface of the outer ring 41 is disposed offset from the end surface of the spigot portion 24 in the axial direction of the shaft 3. The offset amount is the width W2 of the gap 72. Thereby, the end surface of the outer ring retainer 51 and the end surface of the outer ring 41 of the bearing 4 are in proper surface contact, and the axial positioning accuracy of the outer ring retainer 51 is enhanced.

  The third gap 73 (auxiliary gap) is formed at the joint between the shaft body 31 and the output flange 32 of the shaft 3. For example, in the configuration of FIGS. 1 and 2, the end surface of the shaft body 31 and the end surface of the output flange 32 are planes perpendicular to the rotation axis O of the shaft 3 and are disposed to face each other across the width W3. ing. A circular gap 73 is formed at the joint between the shaft body 31 and the output flange 32. A gap 73 communicates with the clearance between the spacer 52 and the outer ring retainer 51.

  In the configuration of FIG. 2, the end surface of the shaft main body 31 is disposed offset from the end surface of the spacer 52 in the axial direction of the shaft 3. The end face of the output flange 32 is disposed in contact with the end face of the spacer 52. The offset amount is the width W3 of the gap 73. Thereby, the end surface of the spacer 52 and the end surface of the output flange 32 are in proper surface contact, and the axial positioning accuracy of the output flange 32 is enhanced.

  In the above configuration, when the shaft 3 rotates, the first gap 71 functions as the labyrinth seal 7 to suppress the gas flow between the clearance on the outer periphery of the shaft 3 and the first chamber 110. Further, the second gap 72 and the third gap 73 increase the axial positioning accuracy of the outer ring presser 51 and the output flange 32 of the shaft body 31, and the influence of dimensional errors of peripheral parts is reduced. The width W1 of the first gap 71 is ensured with high accuracy.

[Modification]
3 and 4 are explanatory views showing a modified example of the labyrinth seal shown in FIG. In these drawings, the same components as those shown in FIG. 2 are denoted by the same reference numerals, and the description thereof is omitted.

  In the configuration of FIG. 2, as described above, the width W <b> 1 of the gap 71 is defined by the step G between the end surface of the outer ring 41 and the end surface of the inner ring 42 of the bearing 4. Such a configuration is preferable in that the axial gauge of the outer ring retainer 51 and the axial gauge of the spacer 52 are set to be the same, and the width W1 of the gap 71 can be defined by the dimensions of the outer ring 41 and the inner ring 42 of the bearing 4. .

  However, the present invention is not limited to this, and as shown in FIG. 3, the outer ring presser 51 and the spacer 52 may have different axial gauges to define the width W <b> 1 of the gap 71. For example, in the configuration of FIG. 3, since the end surface of the outer ring 41 of the bearing 4 and the end surface of the inner ring 42 are on the same plane, the end surface of the outer ring retainer 51 and the end surface of the spacer 52 are the same plane on the bearing 4 side. It is above. On the other hand, since the outer ring retainer 51 and the spacer 52 have different axial gauges, the end surface of the outer ring retainer 51 and the end surface of the spacer 52 are offset from each other on the shaft body 31 side. ing. Thereby, the space | interval (width | variety W1 of the clearance gap 71) of the end surface of the output flange 32 and the end surface of the outer ring holder 51 is ensured appropriately.

  Further, as shown in FIG. 4, the width W <b> 1 of the gap 71 may be adjusted by using the spacer 8. For example, in the configuration of FIG. 4, since the end surface of the outer ring 41 of the bearing 4 and the end surface of the inner ring 42 are on the same plane, the end surface of the outer ring retainer 51 and the end surface of the spacer 52 are the same plane on the bearing 4 side. It is above. Further, the outer ring presser 51 and the spacer 52 have the same axial gauge. In addition, the spacer 8 is disposed between the end face of the spacer 52 and the end face of the inner ring 42. For this reason, the end surface of the outer ring presser 51 and the end surface of the spacer 52 are arranged offset from each other on the shaft body 31 side. Thereby, the space | interval (width | variety W1 of the clearance gap 71) of the end surface of the output flange 32 and the end surface of the outer ring holder 51 is ensured appropriately.

  In addition, the spacer 8 has an annular structure, for example, and can be fitted and arranged on the outer periphery of the shaft 3. Even in the configuration in which the outer ring presser 51 and the spacer 52 have different axial gauges (see FIG. 3), the width W1 of the gap 71 can be easily adjusted by adjusting the thickness of the spacer 8.

  In the configuration of FIG. 2, the labyrinth seal 7 includes the gap 71 formed between the axial end surface of the output flange 32 of the shaft 3 and the axial end surface of the outer ring presser 51 as described above. However, not limited to this, the labyrinth seal 7 may have another gap having a predetermined width in the axial direction of the shaft 3. For example, the shaft 3 has another flange portion that is different from the output flange 32, and the gap having the above-described width is a flange portion that is the rotating system and a stationary system (for example, the housing 2, the outer ring presser 51, etc.). (Not shown).

  Further, the width W1 of the gap 71 may be adjusted by arbitrarily combining the configurations shown in FIGS. In other words, the width W1 of the gap 71 is such that the step G between the end face of the outer ring 41 and the end face of the inner ring 42 of the bearing 4 (see FIG. 2) and the difference in the axial gauge between the outer ring retainer 51 and the spacer 52 (see FIG. 3). ), And any combination of spacers 8 (see FIG. 4).

  5 and 6 are explanatory views showing a modification of the rotating mechanism shown in FIG. In these drawings, the same components as those shown in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted.

  In the configuration of FIG. 1, as described above, the clearance on the outer periphery of the shaft 3 is sealed with the labyrinth seal 7 on the first chamber 110 side and sealed with the magnetic fluid seal 6 on the second chamber 120 side. . For this reason, the clearance of the outer periphery of the shaft 3 in the section from the labyrinth seal 7 to the magnetic fluid seal 6 becomes a substantially sealed space. If the volume of this section is small, there is a new problem that the magnetic fluid seal 6 is easily affected when a large pressure change occurs.

  5 and 6, the rotating mechanism 1 includes the pressure adjusting device 9 for adjusting the air pressure in the section from the labyrinth seal 7 to the magnetic fluid seal 6. Thereby, the influence on the magnetic fluid seal 6 by the pressure change of said area is reduced.

  In the configuration of FIG. 5, the pressure adjusting device 9 includes a tank 91. Further, the tank 91 and the clearance on the outer periphery of the shaft 3 in the section from the labyrinth seal 7 to the magnetic fluid seal 6 are connected via a pipe 94. A first valve 92 is disposed on the pipe 94. A pipe 94 branches from the first valve 92 and the outer peripheral clearance of the shaft 3 and connects to the first chamber 110. A valve 93 is disposed on the branched pipe 94.

  In the configuration of FIG. 5, when the pressure of the first chamber 110 is changed (for example, when the first chamber 110 is changed from an atmospheric atmosphere to a vacuum atmosphere), the first valve 92 is opened and the second valve 93 is Closed. Then, the section from the labyrinth seal 7 to the magnetic fluid seal 6 and the tank 91 communicate with each other, and the volume of this section is increased. The pressure in the tank 91 is set to be approximately equal to the pressure in the space between the labyrinth seal 7 and the magnetic fluid seal 6. Thereby, the pressure change of the area from the labyrinth seal 7 to the magnetic fluid seal 6 is suppressed, and the influence on the magnetic fluid seal 6 is reduced.

  For example, when a reduced pressure environment or a vacuum environment is formed in the first chamber 110, the pressure in the space between the labyrinth seal 7 and the magnetic fluid seal 6 is maintained at a pressure that can suppress burst of the magnetic fluid seal 6. Meanwhile, the first valve 92 and the second valve 93 are closed. Then, the communication between the section from the labyrinth seal 7 to the magnetic fluid seal 6 and the tank 91 is blocked, and the volume of this section is reduced. In this state, an exhaust pump (not shown) in the first chamber 110 is used to exhaust the first chamber 110. Thereby, the leakage of the gas from the inside of the section to the first chamber 110 is suppressed.

  Further, when the pressure in the section from the labyrinth seal 7 to the magnetic fluid seal 6 becomes a specified value or less, the second valve 93 is opened while the first valve 92 is closed. Then, the section from the labyrinth seal 7 to the magnetic fluid seal 6 and the first chamber 110 in a reduced pressure environment or a vacuum environment communicate with each other. In this state, an exhaust pump (not shown) in the first chamber 110 is used to exhaust the first chamber 110. Thereby, the gas in the said area can be exhausted with the gas of the 1st chamber 110. FIG.

  In the configuration of FIG. 6, the pressure adjusting device 9 includes a pump 95. Further, the pump 95 and the clearance on the outer periphery of the shaft 3 in the section from the labyrinth seal 7 to the magnetic fluid seal 6 are connected via a pipe 94. A first valve 92 is disposed on the pipe 94.

  In the configuration of FIG. 6, for example, when a reduced pressure environment or a vacuum environment is formed in the first chamber 110, the valve 92 is opened and the pump 95 sucks the gas in the section from the labyrinth seal 7 to the magnetic fluid seal 6. By doing so, this section is maintained in a low pressure state. On the contrary, for example, when a pressure increasing environment is formed in the first chamber 110, the section is maintained in a high pressure state by the pump 95 pressurizing the section. Thus, the pressure in the section can be freely adjusted.

[effect]
As described above, the rotating mechanism 1 includes the housing 2, the shaft 3 inserted through the housing 2, the bearing 4 installed in the housing 2 to rotatably support the shaft 3, and the outer periphery of the shaft 3. The magnetic fluid seal 6 that seals one clearance (the clearance on the second chamber 120 side in FIG. 1) and the second clearance on the outer periphery of the shaft 3 (the clearance on the first chamber 110 side in FIG. 1) are sealed. A labyrinth seal 7 is provided (see FIG. 1). The labyrinth seal 7 has a gap (first gap) 71 having a predetermined width W1 in the axial direction of the shaft 3 (see FIG. 2).

  In such a configuration, when the shaft 3 rotates, the first gap 71 functions as the labyrinth seal 7 and suppresses the gas flow between the clearance on the outer periphery of the shaft 3 and the first chamber 110. At this time, the pressure in the section from the labyrinth seal 7 to the magnetic fluid seal 6 changes with a delay with respect to the pressure change in the first chamber 110 on the labyrinth seal 7 side. Thereby, the pressure change of the said area is relieve | moderated and there exists an advantage by which the burst of the magnetic fluid seal | sticker 6 is suppressed.

  Further, since the labyrinth seal 7 is a non-contact seal, there is an advantage that the seal function is not easily lowered due to aging or wear, and a burst like a magnetic fluid seal does not occur.

  Further, in the configuration in which the gap 71 has the predetermined width W1 in the axial direction of the shaft 3, the width W1 can be adjusted with a smaller number of parts compared to the configuration in which the gap has a width in the radial direction of the shaft 3. Thereby, there exists an advantage which can form the labyrinth seal 7 easily.

  Further, in this rotating mechanism 1, the labyrinth seal 7 is disposed closer to the sealed space than the magnetic fluid seal 6 side (in FIG. 1, the first chamber 110 side in a reduced pressure environment or a vacuum environment; the low pressure side). (See FIG. 1). In such a configuration, even if the magnetic fluid seal 6 bursts, there is an advantage that the flow of the magnetic fluid to the low pressure side (first chamber 110) is reduced by the labyrinth seal 7.

  The rotating mechanism 1 also includes an outer ring retainer 51 that retains the outer ring 41 of the bearing 4 from the axial direction of the shaft 3 (see FIG. 2). A gap 71 is formed between the flange portion of the shaft 3 (the output flange 32 in FIG. 2) and the outer ring presser 51. In such a configuration, the gap 71 is formed between the flange portion of the shaft 3 that is a rotating system and the outer ring presser 51 that is a stationary system. Thereby, there exists an advantage by which the sealing function of the labyrinth seal 7 is obtained effectively.

  In the rotating mechanism 1, the width W1 of the gap 71 is formed by a step between the end surface of the inner ring 42 and the end surface of the outer ring 41 of the bearing 4 (see FIG. 2). In such a configuration, the axial gauge of the outer ring retainer 51 and the axial gauge of the spacer 52 are set to be the same, and the width W1 of the gap 71 can be defined by the dimensions of the outer ring 41 and the inner ring 42 of the bearing 4. Thereby, there exists an advantage by which parts management becomes easy.

  The rotating mechanism 1 also includes a spacer 52 that is sandwiched between the flange portion of the shaft 3 (the output flange 32 in FIG. 3) and the inner ring 42 of the bearing 4 (see FIG. 3). Further, the width W1 of the gap 71 is formed by the difference G between the axial length of the spacer 52 and the axial length of the outer ring presser 51. In such a configuration, since the end surface of the outer ring 41 of the bearing 4 and the end surface of the inner ring 42 can be arranged on the same plane, there is an advantage that the bearing 4 which is a general-purpose product can be adopted.

  The rotating mechanism 1 includes a spacer 52 disposed between the flange portion of the shaft 3 (the output flange 32 in FIG. 4) and the inner ring 42 of the bearing 4 (see FIG. 4). Further, a width W <b> 1 of the gap 71 is formed by the spacer 8 disposed between the spacer 52 and the inner ring 42 of the bearing 4 or between the spacer 52 and the flange portion 32 of the shaft 3. Such a configuration has an advantage that the width W1 of the gap 71 can be easily adjusted by adjusting the thickness of the spacer 8.

  The rotating mechanism 1 further includes a tank 91 connected to the clearance on the outer periphery of the shaft 3 in the section from the magnetic fluid seal 6 to the labyrinth seal 7 (see FIG. 5). In such a configuration, the volume of the section from the magnetic fluid seal 6 to the labyrinth seal 7 can be increased by the tank 91. Thereby, the pressure change in the section from the labyrinth seal 7 to the magnetic fluid seal 6 is suppressed, and there is an advantage that the influence on the magnetic fluid seal 6 is reduced.

  The rotating mechanism 1 further includes a pump 95 connected to the clearance on the outer periphery of the shaft 3 in the section from the magnetic fluid seal 6 to the labyrinth seal 7 (see FIG. 6). In such a configuration, the pressure in the section from the magnetic fluid seal 6 to the labyrinth seal 7 can be adjusted by the pump 95. Thereby, there exists an advantage by which the influence on the magnetic fluid seal 6 resulting from the pressure change in the said area is reduced.

  1: rotating mechanism, 2: housing, 21: flange part, 211: circumferential groove, 212: O-ring, 22: small diameter part, 23: large diameter part, 24: spigot part, 241: circumferential groove, 242: O ring, 3: Shaft, 31: Shaft body, 32: Output flange, 4: Bearing, 41: Outer ring, 42: Inner ring, 51: Outer ring retainer, 52: Spacer, 6: Magnetic fluid seal, 7: Labyrinth seal, 8: Spacer , 9: pressure adjusting device, 71-73: gap, 91: tank, 92, 93: valve, 94: piping, 95: pump, 100: partition, 101: opening, 110: first chamber, 120: second Room

Claims (10)

A housing; a shaft inserted through the housing; a bearing installed in the housing to rotatably support the shaft; a magnetic fluid seal that seals a first clearance on an outer periphery of the shaft; and an outer periphery of the shaft A labyrinth seal for sealing the second clearance of
The labyrinth seal has a clearance having a predetermined width in the axial direction of the shaft.   The rotating mechanism according to claim 1, wherein the labyrinth seal is disposed closer to the sealed space than the magnetic fluid seal. An outer ring presser that holds the outer ring of the bearing from the axial direction of the shaft; and
The rotation mechanism according to claim 1 or 2, wherein the gap is formed between a flange portion of the shaft and the outer ring retainer.   The rotation mechanism according to any one of claims 1 to 3, wherein a width of the gap is formed by a step between an end face of the inner ring and an end face of the outer ring of the bearing. A spacer disposed between the flange portion of the shaft and the inner ring of the bearing; and
The rotation mechanism according to any one of claims 1 to 4, wherein a width of the gap is formed by a difference between an axial length of the spacer and an axial length of the outer ring retainer. A spacer disposed between the flange portion of the shaft and the inner ring of the bearing; and
The width of the gap is formed by a spacer disposed between the spacer and the inner ring of the bearing or between the spacer and the flange portion of the shaft. The rotating mechanism described.   The rotating mechanism according to any one of claims 1 to 6, further comprising a tank connected to a clearance on an outer periphery of the shaft in a section from the magnetic fluid seal to the labyrinth seal.   The rotation mechanism according to claim 1, further comprising a pump connected to a clearance on an outer periphery of the shaft in a section from the magnetic fluid seal to the labyrinth seal.   A conveying apparatus comprising the rotating mechanism according to claim 1.   A semiconductor manufacturing apparatus comprising the rotating mechanism according to claim 1.

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