JP2019148294A - Degree-of-opening adjustment valve - Google Patents

Abstract

To provide a degree-of-opening adjustment valve that precisely adjusts a gas flow rate, causes little wear, and imposes a low load on a motor shaft.SOLUTION: An opening adjustment valve includes a body 2, a casing 10, a stem 8, a motor 9, and transmission means. The transmission means includes: a bearing holding body 14 fixed by being inserted by an output shaft 9a; a first thrust bearing 15 interposed between the bearing holding body 14 and the motor 9; and a second thrust bearing 16 interposed between the bearing holding body 14 and the stem 8. The output shaft 9a and the stem 8 are in parallel with each other and are separated from each other at a prescribed distance. A surface of the second thrust bearing 16 in contact with the stem 8 is inclined with respect to a plane perpendicular to the output shaft 9a of the motor 9, and a washer 16c on a body side of the second thrust bearing 16 is not subject to a contamination problem due to wear because it keeps a state of being in contact with the stem 8 and does not rotate in conjunction with the bearing holding body 14.SELECTED DRAWING: Figure 1

Description

  The present invention relates to opening adjustment for controlling a fluid flowing in a passage by opening or closing a fluid passage provided in the body, and more particularly, a tilt bearing type in which a tilted bearing is used as a transmission means. The present invention relates to an opening adjustment valve.

  The gas flow valve using the cam described in Patent Document 1 is intended for use in high-precision gas flow applications such as high-pressure gas chromatography, fractional distillation, and semiconductor wafer production. For example, in gas flow management in an epitaxial reactor for manufacturing a semiconductor product, impurities implanted into the substrate surface that determine the degree of conduction of electricity must be controlled very precisely. By using such a precisely controlled gas flow, complex circuits are embedded in the semiconductor wafer.

  Such a process is generally performed by chemical vapor deposition (CVD) in a high temperature oven well known as an epitaxial reactor. In all cases, the various layers are deposited by vapor deposition from gaseous materials. In order to control the deposition and to more accurately control the growth of the layer formed on the substrate surface, the flow rate of the selective gas flowing on the substrate, the exposure time, and the like must be carefully controlled. The degree to which this process can be achieved quickly and accurately greatly increases the yield, thereby reducing the manufacturing cost of the semiconductor product. The valve described in Patent Document 1 (see FIG. 4A) was invented in order to precisely adjust the gas flow rate.

  A cap 128 is provided on the drive shaft 124 of the motor 112, and a cam surface 130 is formed on the lower surface of the cap 128 (see FIG. 4B). The cam surface 130 is substantially perpendicular to the axis 126 that forms the cam rotation axis, but the cam surface 130 is slightly inclined by 1.5 ° with respect to the rotation axis 126 as shown in FIG. Yes. Inner cavity 150 receives a reciprocable plunger or piston 156 having a working surface 158 at the distal end of piston 156 that contacts diaphragm 122. A tapered bore 160 for receiving the ball 162 is provided at the other end of the piston 156. Ball 162 is in contact with cam surface 130 at contact point 170.

  When the drive shaft 124 is rotated 180 ° in the direction indicated by the reference number 172, the ball 162 and the piston 156 are moved upward from the position of FIG. As the drive shaft 124 is further rotated, the piston 156 begins to move downward. As described above, the working end 158 of the piston 156 presses the diaphragm 122 or reduces the pressing force according to the rotation direction and the degree of rotation of the drive shaft 124 to precisely control the gas flow rate.

Japanese Patent No. 4074017

  In the gas flow valve described in Patent Document 1, since the ball 162 rubs without rolling, the surface of the ball 162 or the tapered bore 160 is worn. When the wear particles flow into the gas flow, contamination occurs and causes a decrease in yield. Further, if the wear of the ball 162 exceeds a certain amount, seizure or the like occurs due to an increase in the friction coefficient, the ball 162 does not move, and the gas flow valve does not function.

  A lower surface of the cap 128 fixed to the drive shaft 124 is a cam surface 130. The cam surface 130 presses the piston 156 with a load of 30 to 40 kg. Since this large load is received only by the drive shaft 124 of the motor, the pressing force applied in the axial direction (thrust) is received only by the drive shaft 124 of the motor.

  The thrust load capacity that can be applied to the motor shaft is generally about the weight of the motor, and the limit is about several hundred grams for a motor used in a gas flow valve or the like. If an excessive load is applied to the drive shaft 124, the motor shaft cannot be held at an appropriate position. At the same time, the cam surface is directly subjected to a load of about 30 to 40 kgf, so that an excessive radial is applied to the tip of the motor shaft. If a load is applied and the motor shaft is warped, the shaft may be broken and the motor may be damaged.

  An object of the present invention is an opening adjustment valve capable of precisely adjusting a gas flow rate, wherein the opening adjustment valve has a small amount of wear generated inside the valve and a small axial load applied to the motor shaft. Is to provide.

  The opening adjustment valve according to the present invention (1) opens and closes the fluid passage through the valve body by reciprocatingly moving the body provided with the fluid passage, the casing connected to the body, and the body. And a rotation driving means provided in the casing so that the output shaft protrudes, and a transmission means provided in the casing for converting the rotation of the rotation driving means into a linear motion and transmitting it to the stem. The opening adjusting valve is provided, wherein the transmission means is a bearing holder inserted and fixed to the output shaft of the rotation driving means, and a first holding means interposed between the bearing holding body and the rotation driving means. A thrust bearing, and a second thrust bearing interposed between the bearing holder and the stem, the first and second thrust bearings including a pair of washer and the pair of A thrust bearing having a rolling element disposed between the roadbeds, and the bearing holder has a contact surface with the first thrust bearing parallel to a surface perpendicular to the drive shaft and a contact with the second thrust bearing. The contacting surface is inclined with respect to a surface orthogonal to the drive shaft, and the stem is disposed in parallel with the output shaft, and one end is in contact with the bearing plate of the second thrust bearing.

  The opening adjustment valve includes a body, a casing, a stem, a motor, and transmission means as main components, and has the main characteristics of the transmission means. The transmission means includes a first thrust bearing, a second thrust bearing, and a bearing holder.

  The bearing holder is fixedly inserted through the output shaft of the motor. The first thrust bearing is interposed between the bearing holder and the motor, and the second thrust bearing bearing is interposed between the bearing holder and the stem.

  The first thrust bearing is a thrust bearing having a pair of washer and a rolling element disposed between the pair of washer, and the second thrust bearing is a pair of washer and the pair of Rolling elements disposed between the roadbeds, and a surface in contact with the stem is inclined with respect to a plane perpendicular to the output shaft of the motor.

  The output shaft and the stem are arranged in parallel and separated by a predetermined distance. The body-side washer of the second thrust bearing that comes into contact with the stem rotates using the thrust bearing. It does not occur.

  Since the surface of the second thrust bearing that contacts the stem is inclined with respect to a plane perpendicular to the motor output shaft, for example, if the surface is inclined by a predetermined angle α, the stroke of the stem movement is 2R sin α (here R is the distance from the contact point between the washer on the body side of the second thrust bearing and the stem to the center axis of the output shaft.) Since this stroke is precisely controlled by rotating the motor output shaft at a fine pitch between the angles of 0 ° and 180 °, the flow rate of the fluid can be adjusted very precisely.

  In addition, since the first thrust bearing and the second thrust bearing function as thrust bearings, there is no wear generated between the balls that are the rolling elements and the raceway, and the second thrust bearing and the stem Since it does not slide, it is possible to prevent wear powder like a conventional flow valve from flowing into the fluid. Furthermore, since the stem axial load applied to the stem is received by these thrust bearings, the load applied to the output shaft of the rotation drive means (motor or the like) can be eliminated.

  The opening degree adjusting valve of the present invention (2) is the opening degree adjusting valve of the present invention (1), wherein the first thrust bearing is within the range of the end play which is play in the axial direction of the output shaft of the motor. The bearing holder is fixed to the output shaft so that the rolling element contacts the raceway on the motor side of the first thrust bearing.

  In the electric motor, the motor shaft (output shaft) has play that moves in the thrust direction. Further, since the motor generally preloads the bearing portion with a preload spring, the shaft moves toward the inside of the motor when a thrust load exceeding the preload amount is applied.

  In a state where the rolling element of the first thrust bearing is in contact with the raceway on the motor side of the first thrust bearing, the position where the bearing holder is fixed to the output shaft is within the range of the end play. Therefore, even if the body side washer of the second thrust bearing is urged to the motor side, the urged force is received by the motor side washer of the first thrust bearing. There is no power. This prevents the motor from being damaged.

It is a longitudinal cross-sectional view of the notch of the Example of the opening degree adjustment valve by this invention, and has shown the state which the stem moved to the most downward direction. It is a partially cutaway longitudinal cross-sectional view of the Example of the opening degree adjustment valve | bulb of the Example, and has shown the state which the stem moved to the uppermost direction. It is a figure which shows the relationship between the rotation angle and displacement amount of the Example. A conventional cam operating valve is shown, (a) is a partially cutaway sectional view, (b) is a front view showing the shape of the cam.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. For convenience, the direction of a part or the like may be referred to as up, down, left, or right depending on the direction on the drawing, but these do not limit the scope of the present invention.
FIG. 1 shows a longitudinal sectional view of an embodiment of an opening degree adjusting valve 1 according to the present invention, and shows a state where a stem has moved most downward.

  The body 2 provided with the fluid passages 2a and 2b has a cylindrical protruding portion 11 protruding upward, and a concave portion is formed inside the cylindrical protruding portion 11, and the bonnet 6 is inserted into the concave portion. A ceiling portion 6c having a through hole 6b is formed at the top of the bonnet 6.

  The cylindrical projection 11 and the bonnet nut 12 are fixed by screw joining. A through hole 12b is formed in the upper surface of the bonnet nut 12, and the ceiling portion 6c of the bonnet 6 protrudes upward. When the upper flange portion 12a of the bonnet nut 12 and the flange portion 6a provided on the bonnet 6 come into contact with each other and the bonnet nut 12 is tightened, the bonnet 6 moves downward and comes into contact with the lower end surface of the bonnet 6. The holding adapter 13 is pressed downward, and the valve body (diaphragm) 4 is fixed inside the body 2.

  A recess is formed inside the bonnet 6, and a disk 5 is provided inside the bonnet 6. A flange 5b is formed on the upper part of the disk 5, and a compression coil spring 17 for urging the disk 5 upward is provided in a space between the lower surface of the flange 5b and the upper surface of the holding adapter 13. The valve body presser 5a disposed on the lower surface of the disk 5 presses the valve body 4, the size of the gap between the valve body 4 and the valve seat 3 provided on the body 2 is adjusted, and the amount of fluid flowing is adjusted. Adjusted. A stem 8 passing through the through hole 6 b and the through hole 10 b provided in the bottom wall of the casing 10 is in contact with the upper surface of the disk 5.

  The casing 10 is fixed to the upper surface of the bonnet 6. The casing 10 is formed with a recess 10a whose upper surface is open. The rotational drive means 9 is fixed above the recess 10a. The rotational drive means 9 is not particularly limited, but in the present embodiment, the motor 9 is used. The motor 9 is covered with a motor cover 7. And the output shaft 9a of the motor 9 protrudes in the recessed part 10a.

  In the recess 10a, transmission means which is a main characteristic part of the present invention is provided. The transmission means includes a bearing holder 14 in which the output shaft 9 a of the motor 9 is inserted and fixed, a first thrust bearing 15 interposed between the bearing holder 14 and the motor 9, and the bearing holder 14. A second thrust bearing 16 interposed between the stem 9 and the stem 9 is provided. The output shaft 9a and the stem 8 are parallel and separated by a predetermined distance. The contact surface of the bearing holder 14 with the first thrust bearing 15 is orthogonal to the output shaft 9a, and the contact surface with the second thrust bearing 16 is a predetermined angle α with respect to the surface orthogonal to the output shaft 9a. It is composed only of inclination.

  The first thrust bearing 15 is a thrust bearing having a pair of washer disks 15b and 15c and rolling elements (balls) 15a disposed between the pair of washer disks 15b and 15c. The bearing 16 also has a pair of washer disks 16b and 16c, and rolling elements (balls) 16a disposed between the pair of washer disks 16b and 16c. The second thrust bearing 16 is attached at an angle α to a plane orthogonal to the output shaft 9 a of the motor 9. This is realized by configuring the contact surface of the bearing holder 14 with the second thrust bearing 16 to be inclined by an angle α. The rolling elements (balls) 15a and 16a of the thrust bearings 15 and 16 are held by a so-called cage, but are omitted in the drawing.

  The output shaft 9a and the bearing holder 14 are fixed by fixing bolts 14a, and the raceway 15b is fixed to a non-moving object such as a housing such as the casing 10 so as not to rotate. Since the washer 15c and the washer 16b are fixed to the bearing holder 14, they are forcibly rotated according to the rotation of the output shaft 9a.

  The washer disk 16c is fixed to the lower support 19 and is rotatably supported on the output shaft 9a. The support body 19 has a flange portion at an upper portion, and a cylindrical portion 19a is formed below the flange portion. A concave portion 10b having a smaller diameter than the concave portion 10a that opens to the bottom surface of the concave portion 10a of the casing is formed. An output shaft ball bearing 18 (bearing) is provided between the inner peripheral surface of the cylindrical portion 19a and the outer peripheral surface of the output shaft 9a. This bearing effectively prevents the output shaft 9a of the motor 9 from warping in the radial direction.

  The washer 15b, the rolling element 15a, and the washer 15c form a thrust bearing 15, and the washer 16b, the rolling element 16a, and the washer 16c form a thrust bearing 16.

  As described above, the lower surface 16d of the washer 16c has a slight contact with respect to the horizontal plane orthogonal to the output shaft 9a because the contact surface of the bearing holder 14 with the second thrust bearing 16 is inclined by an angle α. It is inclined by a certain angle α. Since the stem 8 is always urged upward by the compression coil spring 17, and the stem 8 is urged upward by the high-pressure fluid flowing in the fluid passages 2a and 2b, the washer 16c has the washer 16b. The state of contact with the stem 8 is maintained without rotating by the rotation of the output shaft 9a while maintaining the state parallel to the stem 8a. Moreover, the contact part with the stem 8 of the lower surface 16d of the track washer 16c can also form the curved recessed part matched with the curved surface of the front-end | tip part of the stem 8 like the example of a figure.

  In the state of FIG. 1, a state where the stem 8 has moved downward is shown. Since the valve body 4 (diaphragm valve) is in pressure contact with the valve seat 3 in this state, the valve is closed. FIG. 2 shows a state where the output shaft 8 has rotated 180 ° from the state of FIG. The state of FIG. 2 shows a state where the stem 8 has moved most upward. In this state, the valve body 4 (diaphragm valve) is farthest from the valve seat 3, and the valve is 100% open. By rotating the output shaft 9a so that the stem 8 is in a position between the closed state and the 100% open state, the valve open state changes and the fluid flow rate can be finely adjusted.

  Since the thrust bearing is used for rotation, the washer 16c of the second thrust bearing 16 that contacts the stem 8 and the motor-side washer 15b of the first thrust bearing 15 are rotated by the rotation of the output shaft 9a. No wear of the sliding part due to rotation occurs. For this reason, in comparison with the mechanism described in Patent Document 1, there is no possibility that impurities such as wear powder are mixed in the fluid and the yield is lowered.

  Further, if the bearing holder 14 is fixed to the output shaft 9a so that the rolling element 15a is in contact with the raceway 15b within the range of end play which is play in the axial direction of the output shaft 9a of the motor 9, the stem 8 is an upward biasing force by the compression coil spring 17 and a biasing force by which the high-pressure fluid tries to push the disk 5 upward is not directly transmitted to the output shaft 9a. Since it is transmitted and finally transmitted to the washer 15b fixed to a stationary object such as a housing such as the casing 10, no upward force is applied to the output shaft 9a of the motor 9, and the motor 9 is damaged. There is no longer to do.

  FIG. 3 shows the relationship between the rotation angle (plate rotation angle) of the opening adjustment valve according to the present invention and the vertical displacement (valve displacement) of the stem 9. When the plate rotation angle is 0 °, the stem 8 is in the closed state with the lowest position, and when the plate rotation angle is 180 °, the stem 8 is in the most raised state with the highest position. In the present embodiment, the second thrust bearing 16 is inclined with α being 2 °, the maximum valve displacement is 0.45 mm, and the valve displacement is changed by changing the rotation angle within 0 to 180 °. It can be controlled precisely. For example, if the rotation angle is controlled in units of 1 °, the vertical displacement unit of the stem 8 can be precisely adjusted in units of 3 μm. Furthermore, according to this opening degree adjusting valve, there is no sliding portion between the stem and the bearing, and no load in the thrust direction is applied, so that no load is applied to the motor shaft 9a of the motor 9.

1: Opening adjustment valve 2: Body 2a, 2b: Fluid passage 4: Valve body (diaphragm)
8: Stem 9: Motor 9a: Output shaft 10: Casing 14: Bearing holder 15: First thrust bearing 15a: Rolling element (ball)
15b, 15c: washer 16: second thrust bearing 16a: rolling element (ball)
16d: surfaces 16b and 16c in contact with the stem: washer

Claims (2)

A body provided with a fluid passage, a casing connected to the body, a stem disposed in the body and reciprocating to open and close the fluid passage via a valve body, and an output in the casing An opening adjustment valve provided with a rotation drive means provided so that the shaft protrudes, and a transmission means provided in the casing for converting the rotation of the rotation drive means into a linear motion and transmitting it to the stem Because
The transmission means includes
A bearing holder inserted into and fixed to the output shaft of the rotation driving means;
A first thrust bearing interposed between the bearing holder and the rotational drive means;
A second thrust bearing interposed between the bearing holder and the stem;
The first and second thrust bearings are thrust bearings having a pair of washer disks and rolling elements disposed between the pair of washer disks,
The bearing holder has a contact surface with the first thrust bearing parallel to a surface orthogonal to the drive shaft and a surface in contact with the second thrust bearing inclined with respect to a surface orthogonal to the drive shaft;
The stem is an opening adjustment valve that is arranged in parallel with the output shaft and has one end abutting against the washer of the second thrust bearing. The bearing holder so that the rolling element of the first thrust bearing abuts the raceway on the motor side of the first thrust bearing within a range of an end play which is an axial play of the output shaft of the motor. Is fixed to the output shaft. 2. The opening adjusting valve according to claim 1, wherein

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