JP4827502B2 - Rotary motion transmission device - Google Patents

Description

  The present invention relates to a rotational motion transmission device suitable for transmitting rotational motion obtained from a motor outside a vacuum chamber to, for example, a manipulator in a vacuum chamber used for semiconductor manufacturing.

When transmitting rotational driving force obtained from a motor outside the vacuum chamber to a manipulator or the like in a vacuum chamber used for semiconductor manufacturing, it is penetrated and fixed to the chamber wall that separates the atmosphere on the atmosphere side from the atmosphere on the vacuum side. A cylindrical support member that communicates between the two atmospheres; a power transmission shaft that is inserted into the cylindrical support member and supported by a rotary bearing that is built in the cylindrical support member; A rotary motion transmission device having a seal mechanism for sealing a gap between a peripheral surface and a power transmission shaft is known (for example, see Patent Document 1).
JP 2004-63897 A

  However, in the rotational motion transmission device described in Patent Document 1, as a seal mechanism, a seal portion formed by an annular groove having an end that opens toward the atmosphere, and an interior of the annular groove with respect to the rotation shaft. Since a structure having a spring part to contact pressure was adopted, the structure was complicated and it took time and effort to manufacture and assemble, and the cost was increased in the future. There is a problem that it is difficult to uniformly contact the seal portion around the rotation shaft, and the sealing performance does not last long.

  The present invention has been made paying attention to the above-mentioned problems, and the object of the present invention is to provide a rotary motion transmission device that can be manufactured relatively inexpensively at a low cost and has a long sealing performance. Is to provide.

  In order to achieve the above object, the present invention adopts the following configuration. That is, the rotational motion transmission device of the present invention includes a cylindrical support member that is penetrated and fixed to a partition that separates two atmospheres having a difference in atmospheric pressure, such as an atmosphere on the air side and a vacuum side atmosphere, and communicates between the two atmospheres. The power transmission shaft that is inserted into the cylindrical support member and supported by the rotary bearing built in the cylindrical support member, and the gap between the inner peripheral surface of the cylindrical support member and the power transmission shaft are sealed. And a sealing mechanism.

  The seal mechanism is located inside the cylindrical support member, and protrudes in a flange shape on the outer periphery of the power transmission shaft so as to rotate integrally with the power transmission shaft, and is opposed to the ring-shaped rotation plate. And a ring-shaped stationary plate in which the outer peripheral surface is in contact with the inner peripheral surface of the cylindrical support member and is held inside the cylindrical support member, and a power transmission shaft is rotatably inserted in the center hole thereof, and a ring A pressure-type biasing member that presses the ring-shaped stationary plate to the ring-shaped rotating plate by elastically pressing a plurality of circumferentially equidistant locations on the shaped stationary plate via pressurized air, The two atmospheres are sealed through the sliding surfaces of the ring-shaped rotating plate and the ring-shaped stationary plate.

  According to such a configuration, the structure is simple and easy to assemble because it has a basic structure that seals between the two atmospheres while allowing rotational movement through the sliding of the ring-shaped rotating plate and the ring-shaped stationary plate. It is easy and inexpensive to manufacture, and by adjusting the biasing force via pressure, the contact pressure on the sliding surface can be controlled freely, making it easy to maintain sealing performance over a long period of time. .

  In addition, the opposing surface of either the ring-shaped rotating plate or the ring-shaped stationary plate is a tapered surface that is inclined along the radial direction and the surface is smoothed (such as lapping). If it is made of a hard material that is less likely to wear than the facing surface of the other member, the outer circumferential edge of the sliding surface will be radially outward as wear of the facing surface of the other member proceeds. As a result of movement or expansion, a smooth surface that is not worn always appears, and as a result, the smooth facing surface (tapered surface) of one member and the smooth facing surface of the other member slide together. As a result, the sealing performance is maintained over a long period of time.

  Furthermore, if the surface facing the taper surface is a curved surface that is curved along the radial direction, the amount of dust generated due to frictional wear with the taper surface is reduced, effectively preventing dust from entering the vacuum side. It can be reduced.

  According to the rotational motion transmission device of the present invention, the basic structure is such that both atmospheres are sealed through the sliding of a ring-shaped rotating plate and a ring-shaped stationary plate that are uniformly pressed at multiple points in the circumferential direction via pressurized air. In addition to having good sealing performance, the structure is simple and easy to assemble, and can be manufactured at low cost. Therefore, it is easy to maintain the sealing performance over a long period of time.

  Hereinafter, a preferred embodiment of a rotational motion transmission device according to the present invention will be described in detail with reference to the accompanying drawings.

  The rotational motion transmission device 1 shown in this embodiment is applied to a vacuum chamber used for semiconductor manufacturing. As is well known, the inside of a vacuum chamber used for semiconductor manufacturing must be maintained at a high vacuum, and must be kept from being shielded from external magnetic and electrostatic influences. For this reason, even when a motor is used to operate a manipulator in the vacuum chamber, all the motors and the like serving as the driving source are placed outside the vacuum chamber in consideration of the magnetic and electrical influences from the motor. It is customary. Therefore, in order to transmit the rotational driving force obtained from the motor outside the vacuum chamber to a manipulator or the like in the vacuum chamber, the rotational motion transmission device according to the present invention is employed.

  A cross-sectional view of a rotary motion transmission device according to the present invention is shown in FIG. As shown in the figure, the rotary motion transmitting device 1 includes a cylindrical support member 3, a power transmission shaft 4, a rotary bearing 5, a ring-shaped rotating plate 6, a ring-shaped stationary plate 7, and a pneumatic type attachment. And a biasing member 8. In addition, what is shown with the code | symbol 2 is a container wall of a vacuum chamber.

  The cylindrical support member 3 is penetrated and fixed to the container wall 2 that functions as a partition wall that separates the inside of the vacuum chamber from the atmosphere, and communicates between the two atmospheres. In this example, the cylindrical support member 3 and the container wall 2 are fixed by inserting a bolt (not shown) through the flange portion 3a of the cylindrical support member 3.

  The power transmission shaft 4 is connected to a driving shaft of a motor (not shown) at an end portion on the atmosphere side, and an operation shaft of a manipulator (not shown) is connected to an end portion in the vacuum chamber. The power transmission shaft 4 is inserted into the cylindrical support member 3 and is rotatably supported via a rotary bearing 5 housed in the cylindrical support member 3.

  A seal mechanism is provided in the gap between the inner peripheral surface of the cylindrical support member 3 and the power transmission shaft 4 to seal it. The illustrated sealing mechanism includes a ring-shaped rotating plate 6, a ring-shaped stationary plate 7, and a pressure type urging member 8.

  The ring-shaped rotating plate 6 is located inside the cylindrical support member 3, is projected in a flange shape on the outer periphery of the power transmission shaft 4, and rotates integrally with the power transmission shaft 4. In the illustrated example, the material of the ring-shaped rotating plate 6 is a metal such as SUS or Al, or ceramic. As a fixing means between the power transmission shaft 4 and the ring-shaped rotating plate 6, a known coupling means such as press fitting may be appropriately employed.

  The ring-shaped stationary plate 7 faces the ring-shaped rotating plate 6 and is held inside the cylindrical support member 3 with its outer peripheral surface being in contact with the inner peripheral surface of the cylindrical support member 3, and in the central hole 7b. The power transmission shaft 4 is rotatably inserted. In the illustrated example, a resin (for example, ultrahigh molecular weight polyethylene such as PET) is employed as the material of the ring-shaped stationary plate 7. Although not shown, a known sealing means such as an O-ring is preferably interposed in the gap between the outer peripheral surface of the ring-shaped stationary plate 7 and the inner peripheral surface of the cylindrical support member 3.

  The pneumatic urging member 8 is composed of a metal or resin ring-shaped block body, and has six ultra-small air cylinders at equal intervals along the circumference on the surface facing the ring-shaped stationary plate 7. (Commercially available miniature cylinders) 9, 9... Are embedded. Each of these air cylinders 9, 9... Is provided with a presser (not shown) so as to be able to protrude and retract, and as shown in FIG. The six points c1 to c6 on the circumference of 7 are pressed with a uniform force. These air cylinders 9 are connected to a common pressurized air source via an air passage 10. The pressure of the pressurized air supplied from the pressurized air source to each air cylinder can be adjusted via a pressure regulator (not shown). Therefore, the pressing force by the air cylinder can be appropriately controlled by operating this pressure regulator.

  As described above, the pressure type urging member 8 elastically presses the circumferentially equidistant portions c1 to c6 on the ring-shaped stationary plate 7 via the pressure air, thereby causing the ring-shaped stationary plate 7 to be in a ring shape. It has a function of pressing the rotating plate 6 with a uniform pressure. Thereby, it is comprised so that both atmospheres may be sealed favorably through the sliding surface of the ring-shaped rotating plate 6 and the ring-shaped stationary plate 7.

  As shown in FIGS. 2 and 3, the ring-shaped stationary plate 7 includes a large-diameter base 71 and a small-diameter stepped portion 72 in this example. And the end surface of the step part 72 of small diameter is made into the opposing surface 7a with the ring-shaped rotating plate 6, ie, the sliding surface. The facing surface 7 a is subjected to a smoothing process and is parallel to a surface perpendicular to the power transmission shaft 4. On the other hand, the opposed surface 6a of the ring-shaped rotating plate 6 to the ring-shaped stationary plate 7 is a tapered surface that is inclined along the radial direction and the surface is smoothed (lapped).

  As described above, the material of the ring-shaped rotating plate 6 is SUS-based or Al-based metal or ceramic, while the material of the ring-shaped stationary plate 7 is a resin such as PET. ing. Therefore, the tapered surface (opposing surface 6 a) of the ring-shaped rotating plate 6 has a hardness relationship that is less likely to be worn than the opposing surface 7 a of the ring-shaped stationary plate 7.

  An explanatory view showing the relationship between the wear of the ring-shaped stationary plate and the movement of the peripheral edge of the sliding surface is shown in FIG. As shown in the figure, when the power transmission shaft 4 rotates with the rotation of a motor (not shown), an opposing surface (tapered surface) 6a on the ring-shaped rotating plate 6 side and an opposing surface 7a on the ring-shaped stationary plate 7 side Will be in a rotating state where the two are rubbed together.

  At this time, both the facing surfaces 6a and 7a have high altitudes on the sliding surfaces of the both in addition to the contact pressure being uniform at each point along the circumference due to the action of the pneumatic biasing member 8. Since the surfaces are smoothed, the two come into close contact with each other to obtain good sealing performance.

  Initially, the ring-shaped rotating plate 6 and the ring-shaped stationary plate 7 are in contact with each other along the circumference at the peripheral edge P1 of the sliding surface, but with the passage of time, wear is determined to a degree determined by the contact pressure and the materials of both. proceed. At this time, due to hardness, the facing surface (tapered surface) 6a on the ring-shaped rotating plate 6 side is maintained with little wear, whereas the facing surface 7a on the ring-shaped stationary plate 7 side is worn. Therefore, as the wear progresses, the periphery of the sliding surface moves radially outward from P1 to Px along the opposing surface (tapered surface) 6a.

  In the drawing, the taper surface is depicted as moving from 6a to 6a ', but in actuality, the taper surface 6a side is fixed, and wear on the facing surface 7a side proceeds. That will be readily understood by those skilled in the art.

  At this time, since a smooth surface layer (opposing surface 7a) that has been smoothed always appears at the new peripheral edge Px of the rubbing surface, the opposing surface 7a is worn over the entire radial width of the end surface of the stepped portion 72. In the meantime, both are in close contact with each other and good sealing performance is maintained.

  A cross-sectional view (part 1) showing another example of the seal portion is shown in FIG. In this example, the surface 7a facing the tapered surface 6a of the ring-shaped rotating plate 6 of the ring-shaped stationary plate 7 is a curved surface that is curved along the radial direction. More specifically, the curved surface includes a first curved surface 73 having a small curvature and a second curved surface 74 having a large curvature. Further, a ring-shaped cut groove 75 is formed on the outer periphery of the small diameter step portion 72, and the curved portions 73 and 74 are given elasticity by the action of the cut groove 75.

  According to such a configuration, when the tapered surface 6 a of the ring-shaped rotating plate 6 and the opposing surface 7 a of the ring-shaped stationary plate 7 rotate while being pressed against each other, the curved portions 73 and 74 are appropriately bent by the action of the cut groove 75. Thus, good sealing performance can be obtained by close point contact between the two. Further, as the curved portions 73 and 74 are worn, the contact points of both of them gradually move inward in the radial direction, and the contact with the smooth surface is always maintained. Maintained well. In addition, since the first curved portion 73 that hardly contributes to the sealing action has a small curvature, the escape space is secured and the generation of dust due to wear is small, while the second curved portion 74 contributing to the sealing action has a curvature. Due to the large size, the generation of dust due to wear is small while in contact with the tapered surface 6a. Therefore, according to this example, the amount of dust generated due to frictional wear with the tapered surface is reduced, and dust contamination on the vacuum side can be effectively reduced.

  A cross-sectional view (part 1) showing another example of the seal portion is shown in FIG. The taper surface 6a shown in FIG. 4 has a form that becomes a convex portion, whereas the taper surface 6a shown in FIG. 5 has a form that becomes a concave portion, and the taper surface 6a can have any form of unevenness. Good. As in the example of FIG. 4, this example also has an advantage that good sealing performance is maintained for a long time and generation of dust due to wear is suppressed as much as possible. In the figure, the same components as those in FIG.

  In the above-described embodiment, the opposing surface 6a side of the opposing surface 6a of the ring-shaped rotating plate 6 and the opposing surface 7a on the ring-shaped stationary plate 7 side is a tapered surface. The side of the surface 7a can be a tapered surface. In this case, in order to obtain the above-described hardness relationship, a resin may be used as the material of the ring-shaped rotating plate 6 and the material of the ring-shaped stationary plate 7 may be a metal.

  According to the rotational motion transmission device of the present invention, the basic structure is such that both atmospheres are sealed through the sliding of a ring-shaped rotating plate and a ring-shaped stationary plate that are uniformly pressed at multiple points in the circumferential direction via pressurized air. In addition to having good sealing performance, the structure is simple and easy to assemble, and can be manufactured at low cost. Since the contact pressure can be freely controlled, it is easy to maintain the sealing performance over a long period of time, and it is suitable for, for example, a vacuum chamber used for semiconductor manufacturing.

It is sectional drawing of the power transmission device which concerns on this invention. It is a detailed explanatory view of a ring-shaped stationary plate. It is explanatory drawing which shows the relationship between the abrasion of a ring-shaped stationary plate, and the movement of a sliding surface peripheral part. It is sectional drawing (the 1) which shows the other example of a seal | sticker part. It is sectional drawing (the 2) which shows the other example of a seal | sticker part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power transmission device 2 Vacuum chamber container wall 3 Cylindrical support member 3a Mounting flange 4 Power transmission shaft 5 Rotating bearing 6 Ring-shaped rotating plate 6a, 6a 'Opposing surface (tapered surface)
7 Ring-shaped stationary plate 7a Opposing surface 7b Center hole 8 Pneumatic pressure biasing member 9 Air cylinder 10 Air passage 71 Base 72 Step part 73 First curved part 74 Second curved part 75 Ring-shaped cut groove c1 to c6 Air cylinder Pressing position by plunger of P1, Px Periphery of sliding surface

Claims (1)

A cylindrical support member that penetrates and is fixed to a partition wall that separates two atmospheres where there is a difference in atmospheric pressure, such as an air atmosphere and a vacuum atmosphere, and communicates between the two atmospheres;
A power transmission shaft which is supported via a rotary bearing which is furnished in inserted through and the tubular support member to the inside of the tubular support member,
And a sealing mechanism for sealing the gap between the power transmission shaft and the inner peripheral surface of the tubular support member,
The sealing mechanism is
In the interior of the tubular support member, and the ring-shaped rotary plate which rotates integrally with the power transmission shaft projecting from the flange on the outer periphery of the power transmission shaft,
Is held to the ring-shaped rotary plate facing One only its outer peripheral surface in the interior of the tubular support member in contact with the inner circumferential surface of the tubular support member, said power transmission shaft is rotatably at its center hole A ring-shaped stationary plate inserted through,
By elastically pressing through the gas in the circumferential direction at equal intervals of a plurality of positions on the ring-shaped stationary plate, a gas urging expression member to the ring-shaped stationary plate is pressed against to the ring-shaped rotary plate, the Including
The facing surface of either the ring-shaped rotating plate or the ring-shaped stationary plate is a tapered surface that is inclined along the radial direction and has a smooth surface, and the tapered surface is the facing surface of the other member. Made of hard material that is less likely to wear than the surface,
The surface facing the tapered surface is a curved surface that is curved while bulging toward the other side along the radial direction, and the curved surface is a first curved surface with a small curvature located on the side close to the tapered surface ( 73) and a second curved surface (75) having a large curvature located on the side far from the tapered surface, and the first curved surface is provided on the peripheral side surface of the first curved surface (73). A ring-shaped cut groove (75) cut from the (73) side to the second curved surface (75) side is formed,
A rotary motion transmission device characterized by sealing between the two atmospheres via a sliding surface between a ring-shaped rotating plate and a ring-shaped stationary plate.

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