JP2989402B2 - Vacuum valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the prevention of leakage of an opening and closing device for a vacuum valve used in a vacuum exhaust device, a vacuum vessel, and the like.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional vacuum valve. Reference numeral 30 denotes a disc-shaped valve body that opens and closes the opening 25 of the vacuum vessel 20.
A straight shaft 61 is connected to the valve body 30 via a valve shaft connecting portion 40. The straight shaft 61 passes through the inside of the off-axis tube 50 and is connected to the piston of the pneumatic cylinder 91. Off-axis tube 5
An O-ring 81 for hermetically sealing the space between the shaft 61 and the straight shaft 61
Are provided. When air pressure is supplied to the chamber on the left side of the figure in the pneumatic cylinder 91 and the piston is pushed to the right, the straight-moving shaft 61 and the valve body 30 move to the right with the piston. When the valve element 30 reaches the position indicated by the chain line, the valve stem coupling portion 40 presses the valve element 30 against the opening 25, and the valve element 30 hermetically seals the opening 25.

[0003]

The conventional vacuum valve is as described above. However, the O-ring 81 for hermetically sealing around the rectilinear shaft 61 has a problem that the rectilinear shaft 61 presses and reciprocates in the axial direction. , Large internal stresses and strains are generated in the O-ring 81 due to frictional force, and leakage is likely to occur, and wear and abrasion are large.
There were problems such as rapid deterioration and short life.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has as its object to obtain a vacuum valve having a long service life in which leakage, wear, deterioration, and the like hardly occur.

[0005]

A vacuum valve according to the present invention comprises a valve element for opening and closing an opening of a vacuum container, a hollow linear shaft having one end connected to the valve element via a joint, and A nut body having a detent attached to the other end of the straight shaft, and a screw having a length exceeding the moving distance of the valve body, which is screwed into the nut body, enters into the hollow of the straight shaft, and is formed. A screw shaft, a rotary shaft having one end connected to the screw shaft and the other end connected to a rotary drive unit, and the linear shaft, the nut body, the screw shaft, and the rotary shaft being housed therein and the linear shaft being inside the vacuum vessel. One end extending to the vacuum container is hermetically fixed to the vacuum container, and the other end is fitted to an off-axis tube formed so that the rotating shaft passes therethrough, so that the detent of the nut body can move in the axial direction. A guide ridge provided on the inner surface of the off-axis tube in the axial direction, and the rotating shaft of the off-axis tube Those comprising a seal member provided so as to hermetically seal between the shaft outer tube at a location that penetrates the rotary shaft.

[0006]

In the vacuum valve according to the present invention, when the rotary drive rotates the rotary shaft, the screw shaft connected to the rotary shaft also rotates. Since the rotation stopper of the nut body screwed to the screw shaft is fitted to the guide ridge so as to be movable in the axial direction, when the screw shaft rotates, the nut body moves in the axial direction by the screw action. When the nut body moves in the axial direction, the straight-moving shaft connected to the nut body also moves in the axial direction, the straight-moving shaft moves the valve body through the connecting part, and the valve body opens and closes the opening of the vacuum vessel. At this time, the seal member provided in the rotary shaft penetrating portion of the off-axis tube is in contact with the rotary shaft, and is in contact with the rotary motion surface in the direction of the seal line, which is a rotational motion. And no large internal stress is generated, the seal member is less worn and worn, leaks less, and hermetically seals.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, reference numeral 20 denotes a vacuum container, and reference numeral 30 denotes a valve body that opens and closes an opening 25 of the vacuum container 20. Valve body 30
Has a disc shape, and a valve shaft connecting portion 40 is provided at the center of the valve body 30.
The right end of the straight shaft 61 in the figure is connected to the valve shaft connecting portion 40. The rectilinear shaft 61 has a hollow cylindrical shape, and a nut 64 is fixed to the left end of the rectilinear shaft 61 in the drawing. Further, a screw shaft 63 that is screw-fitted into the nut body 64 is provided, and the screw shaft 63 is connected to the left side in the drawing by the same axis and is provided with a rotating shaft 62. The rotating shaft 62 is rotationally driven by an electric motor 92. It is configured to be. An off-axis tube 50 is provided so as to accommodate the linear shaft 61, the screw shaft 63, the nut body 64, and the rotating shaft 62. The right end of the off-axis tube 50 in the figure is fixed to the vacuum vessel 20 with a flange 52 in an airtight manner. Have been. The rotating shaft 62 is rotatably supported on the off-axis tube 50 by a radial bearing 55, and is supported by a thrust bearing (not shown) inside the electric motor 92 and near the radial bearing 55 so as not to move in the axial direction. A magnetic fluid seal 82 is provided as a sealing member for hermetically sealing the space between the rotating shaft 62 and the off-axis tube 50 at a position where the rotating shaft 62 passes through the end of the off-axis tube 50. Of course, as a sealing member,
Conventional sealing means such as an O-ring and gland packing can also be used.

FIG. 2 shows the details of the drive shaft. As shown in FIGS. 1 and 2, a hollow cylindrical linear shaft 6 is provided in an off-axis tube 50.
1 is provided so as to be movable in the axial direction, the axially movable range of the rectilinear shaft 61 is larger than the required opening and closing movement range of the valve 30, and the nut 64 fixed to the rectilinear shaft 61 Since the movement range is also equal to or greater than the required opening / closing movement range of the valve body 30, the length of the screw shaft 63 is also required to be equal to or greater than the required opening / closing movement range of the valve body 30. In this example,
As shown in FIG. 2, the screw shaft 63 is a ball screw shaft,
Inside the nut body 64, a ball female screw that is screwed with the ball screw of the screw shaft 63 is formed, and the screw shaft 63 and the nut body 64 are fitted with a large number of balls (steel balls) that fit into both ball screw concave strips. ) So that the nut body 64
A number of balls are circulated therein.

As shown in FIG. 2, one or more guide protrusions 57 extending in the axial direction are provided on the inner surface of the off-axis tube 50, and the guide protrusions 57 are provided on the outer peripheral surface of the nut body 64. Is provided with a detent 67 slidably fitted to the nut body 6.
4 is supported by an off-axis tube 50 so as to be non-rotatable and slidable in the axial direction. The range of attachment of the guide ridge 57 is the nut body 6
The movable range is equal to or larger than the movable range of 4, that is, the movable range of opening and closing of the valve element 30.

Next, the operation of the embodiment shown in FIGS. 1 and 2 will be described. The figure shows the open state of this vacuum valve. When the rotary shaft 62 is driven to rotate counterclockwise when viewed from the left side of the drawing by an electric motor 92 which is a rotary drive unit of the vacuum valve, the screw shaft 63 connected to the rotary shaft 62 also rotates counterclockwise. . The rotating shaft 62 is supported by a thrust bearing before and after the radial bearing 55 and inside the electric motor 92 so as not to move in the axial direction, and the screw shaft 63 connected to the rotating shaft 62 is also unable to move in the axial direction. . Since the rotation stopper 67 of the nut body 64 screwed to the screw shaft 63 is fitted to the guide ridge 57 of the off-axis tube 50 so as not to rotate and slide freely in the axial direction, the screw shaft 63 is rotated counterclockwise. , The screw shaft 63 cannot move in the axial direction, and the nut body 64 is moved to the right in the axial direction by the wedge action of the screw. When the nut body 64 moves in the axial direction, the rectilinear shaft 61 connected to the nut body 64 also moves to the right in the axial direction, and the rectilinear shaft 61 moves the valve body 30 through the valve shaft connecting portion 40 to the right in the figure. Move to the direction. When the valve 30 moves to the position shown by the chain line in FIG.
To close the opening 25.

When the vacuum valve is opened, first, in FIGS. 1 and 2, the valve shaft connecting portion 40 is operated to open the valve body 30 covering the opening 25 of the vacuum vessel 20 and closing it. Away from Next, the electric motor 92 is rotated in the reverse direction to rotate the rotating shaft 62 and the screw shaft 63 clockwise. Then, the nut body 64 screwed to the screw shaft 63 moves leftward in the axial direction in the figure due to the wedge action of the screw, and
Then, the valve 30 is moved to the left via the valve shaft coupling portion 40, and the valve 30 is opened.

In the above operation, the sealing member 80 provided in the rotary shaft penetrating portion of the off-axis tube 50 contacts the rotary shaft 62 and seals while being in contact with the rotary motion surface in the direction of the seal line. The sealing member 8
If an O-ring, gland packing, or the like is used as 0, no excessive deformation occurs in the seal member 80 and no large internal stress or internal distortion occurs. There is little leakage between the shaft and the shaft 62, and it has a long life and good airtight sealing. Also, in the vacuum valve shown in FIG.
However, since the vacuum valve is configured to be hermetically sealed with respect to the rotating shaft, there is no possibility that the magnetic fluid moves in the axial direction, and the magnetic fluid seal 82 can be easily adopted. it can.

In the above embodiment, the ball screw shaft 63 and the ball nut body 64 are used as means for converting the rotational movement of the rotary shaft 62 into a linear movement in the axial direction. . However, in a device relating to vacuum, since the presence of lubricating oil and the like may degrade vacuum performance, it is desirable to employ a ball screw transmission means that does not require lubricating oil and the like.

In FIG. 1, a magnetic fluid seal 82 is employed as a seal member 80 for hermetically sealing the space between the off-axis tube 50 and the rotary shaft 62. Instead of the seal 82, a conventional sealing means such as an O-ring or gland packing can be used.

In the above-described embodiment, the guide ridges 5 provided on the off-axis tube 50 are used as the detent guide means for the nut body 64.
7 and a detent 67 that fits externally on the guide ridge 57 provided on the nut body 64, but a guide groove is provided instead of the guide ridge 57, and the detent 67 is fitted inside the guide groove. It may be a convex shape. Further, a motor operated by air pressure may be used instead of the electric motor 92.

[0016]

As described above, according to the present invention, the rotary motion of the rotary shaft is converted into the linear motion by the screw shaft and the nut, and the valve is driven to hermetically seal the rotary shaft. With this configuration, there is no leakage, and wear and abrasion of the seal member can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a vacuum valve according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a drive shaft portion of a vacuum valve according to one embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a conventional vacuum valve.

[Explanation of symbols]

20: Vacuum container, 25: Opening, 30: Valve body, 40: Valve shaft connecting part, 50: Off-axis tube, 57: Guide ridge, 61: Straight running shaft, 62: Rotating shaft, 63: Screw shaft, 64: Nut body, 67: Non-rotating, 80: Seal member, 82: Magnetic fluid seal, 92: Electric motor.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-212579 (JP, A) JP-A-60-23303 (JP, U) JP-A-51-59909 (JP, U) 43191 (JP, B2) Jiko 62-22702 (JP, Y2) (58) Fields investigated (Int. Cl. ⁶ , DB name) F16K 31/00-31/04 F16K 31/44-31/50 F16K 51/00-51/02 F16K 41/04 F16J 15/16

Claims (1)

(57) [Claims] 1. A valve body for opening and closing an opening of a vacuum container, a hollow straight shaft having one end connected to the valve body via a coupling portion, and a detent provided at the other end of the straight shaft. A nut having a screw body, a screw shaft which is screwed into the nut body, enters a hollow of the straight-moving shaft, and is formed with a screw having a length exceeding a moving distance of the valve body, and one end is connected to the screw shaft. The other end accommodates a rotating shaft connected to a rotation drive unit, the straight-moving shaft, the nut body, the screw shaft and the rotating shaft, and one end of which the straight-moving shaft extends into the vacuum vessel is hermetically fixed to the vacuum vessel. The other end is provided in the axial direction on the inner surface of the outer shaft tube so that the detent of the nut body fits movably in the axial direction with the outer shaft tube formed so that the rotating shaft passes therethrough. Between the off-axis tube and the rotating shaft at a location where the rotating shaft of the off-axis tube penetrates. A vacuum valve comprising: a sealing member provided to hermetically seal.