JP2004324833A - Fluid controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid controller using a linear-drive stepping motor as a driving device and capable of transmitting movement of a moving body of the driving device to a stem of the fluid controller without deteriorating accuracy. <P>SOLUTION: As the driving device 5 for vertically moving the stem 3, the linear-drive stepping motor having the moving body 16, which vertically moves, is used. An upper end of the stem 3 is provided with a moving body receiver 23 for receiving a lower end of the moving body 16 of the driving device 5, and the moving receiver 23 is energized upward by an elastic member 24 to abut on the moving body 16 from under thereof in the condition that an upward load is always applied. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fluid controller used in a pipe or a fluid control device.
[0002]
[Prior art]
Conventionally, a body having a fluid inflow passage, a fluid outflow passage, and a communication passage communicating the two passages, and a stem whose distal end portion blocks or opens the communication passage by being vertically moved in a vertical passage including the communication passage Fluid controllers having a drive device for moving the stem up and down are well known, and among them, those using a stepping motor as the drive device have the advantage of high positioning accuracy, It is suitably used when a minute amount of control is required (Patent Document 1).
[0003]
[Patent Document 1]
JP-A-60-263784
[Problems to be solved by the invention]
The fluid controller using the stepping motor requires a mechanism for converting the rotation of the motor into a vertical movement, and there is a problem that the vertical length of the fluid controller becomes large due to the installation space of the mechanism.
[0005]
On the other hand, a linear drive stepping motor having a moving body that moves up and down has been developed as a drive device, and it is conceivable to use this drive device for a fluid controller. In this case, the connection means for connecting the moving body of the drive device and the stem of the fluid controller does not cause backlash or misalignment, and the movement of the moving body does not impair the accuracy of the stem of the fluid controller. Communication is a new challenge.
[0006]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a fluid controller that uses a linear drive stepping motor as a drive device and that moves a moving body of the drive device to a stem of the fluid controller without impairing accuracy. .
[0007]
Means for Solving the Problems and Effects of the Invention
A fluid controller according to the present invention includes a body having a fluid inflow passage, a fluid outflow passage, and a communication passage communicating the two passages, and a distal end portion that is moved vertically in a vertical passage including the communication passage so that a distal end thereof is a communication passage In a fluid controller comprising a stem that shuts off or opens, and a driving device that moves the stem up and down, the driving device is a linear drive stepping motor having a moving body that moves up and down, and at the upper end of the stem, A moving body receiver for receiving a lower end of the moving body of the driving device is provided, and the moving body receiver is urged upward by an elastic member to contact the moving body from below with an upward load constantly applied. It is characterized by being carried out.
[0008]
According to the fluid controller of the present invention, the size of the fluid controller can be reduced by using a linear driving stepping motor as the driving device, and the moving body receiver is urged upward by the elastic member, Since the moving body of the drive unit and the stem are not connected by welding, screws, etc., the moving body of the drive unit is moved because the moving body and the stem of the drive unit are not connected by welding, screws, etc. Is transmitted to the stem without play, and a fluid controller with high resolution that does not impair the advantage of high positioning accuracy of the stepping motor can be obtained.
[0009]
As the driving device, for example, a device in which a screw mechanism is provided in a rotor of a stepping motor and a shaft (moving body) is linearly moved is used. In this case, the axial play generated between the male screw and the female screw constituting the screw mechanism is a problem in the fluid controller that controls a small amount, but the elastic member constantly pushes the moving body upward. Even when a screw mechanism is provided in the rotor, it is possible to eliminate the backlash in the axial direction.
[0010]
It is preferable that the lower end surface of the moving body of the driving device is formed in an arc shape in a vertical section, and a recess is formed in the upper end of the moving body receiver. With this configuration, the elastic member urges the moving body receiver upward in a state where the lower end portion of the moving body is fitted into the recess of the moving body receiver, so that the positioning at the time of mounting the driving device can be easily performed. Even if there is a misalignment between the axis of the moving body and the axis of the stem, the misalignment can be absorbed to such an extent that there is no problem in operation.
[0011]
The bottom surface of the recess may be a flat surface or an arc-shaped cross section. Even if it is a flat bottom surface, there is no problem in operation at all, but by forming an arc-shaped bottom surface, the lower end surface of the vertical cross-section of the moving body of the drive unit abuts the arc-shaped bottom surface of the moving-body receiver. In this state, the elastic member urges the moving body receiver upward, so that the misalignment between the moving body axis and the stem axis is more reliably absorbed.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In the following description, left and right refer to the left and right of the figure.
[0013]
FIG. 1 shows a first embodiment of the fluid controller of the present invention.
[0014]
The fluid controller (1) of this embodiment includes a bottomed cylindrical body (2) having a tubular left protrusion (7) and a tubular right protrusion (8) at its lower part, and a body (2). A cylindrical stem (3) movably inserted into the inside, a cylindrical holder (4) fitted over the upper end of the body (2), and a driving device ( 5) and connecting means (6) for connecting the stem and the driving device housed in the holder (4).
[0015]
The driving device (5) is a linear driving stepping motor, and includes a casing (11), a stator and a rotor (not shown) housed in the casing (11), and a lower part from a lower wall of the casing (11). And a moving body (16) projecting therefrom.
[0016]
The casing (11) of the drive device (5) and the holder (4) are connected to the casing (4) provided at regular intervals on the disk-shaped flange portion (4a) at the upper end of the holder (4). 11) Bolts (12) penetrating the projecting portion (17) of the lower wall are joined by screwing.
[0017]
At the lower end of the body (2), a fluid inflow passage (2a) extending slightly to the left from near the center and leading to the inside of the left protruding portion (7), and a center end of the fluid inflow passage (2a). A communication passage (2b) extending upwardly and a right protrusion (8) extending rightward from a lower end of a stem guide path (19) extending from an upper end of the communication passage (2b) to an upper end of the body (2). A fluid outflow passage (2c) communicating with the inner passage is provided.
[0018]
The lower end portion (3a) of the stem (3) has a tapered conical shape, and a lower flange portion (3b) is provided above the conical portion (3a). An upper flange portion (20) and a seal member (26) are provided at an upper end portion of the body (2) to guide the stem (3) so that the stem (3) can move up and down and prevent fluid leakage from the stem guide path (19). ing. A bellows (21) is provided between the lower surface of the upper flange portion (20) and the upper surface of the lower flange portion (3b) of the stem (3). A guide packing (27) serving as a guide for the stem (3) is arranged between the inner periphery of the upper flange portion (20) and the outer periphery of the stem (3).
[0019]
The upper end of the stem (3) is above the upper end of the body (2), and a male thread (22) is formed at the upper end of the stem (3). A lower part of a moving body receiver (23) for receiving the moving body (16) of the driving device (5) is screwed to the male screw portion (22).
[0020]
The connecting means (6) for connecting the stem to the driving device comprises a moving body receiver (23) and a compression coil spring (24) as an elastic member for biasing the moving body receiver.
[0021]
The moving body receiver (23) is formed in a stepped cylindrical shape, and a flange portion (23a) at an upper end thereof has a sufficient clearance with respect to an inner periphery of the holder (4) and is slidable. I have. An inward flange portion (4c) is provided near the lower end of the holder (4). The upper surface of the inward flange portion (4c) and the lower surface of the upper flange portion (23a) of the moving body receiver (23). Thus, a compression coil spring (elastic member) (24) for urging the moving body receiver (23) upward is received. Thus, the moving body receiver (23) is brought into contact with the moving body (16) from below with an upward load constantly applied.
[0022]
The lower end of the moving body (16) of the driving device (5) is formed in a convex circular arc shape in vertical section, and has an arc-shaped bottom surface at the upper end of the moving body receiver (23). A recess (23b) into which the portion is fitted is formed. The diameter of the recess (23b) is slightly larger than the diameter of the lower end of the moving body (16), and the radius of the arc-shaped bottom surface of the recess (23b) is convex at the lower end of the moving body (16). It is formed slightly larger than the radius of the arcuate surface. Therefore, the lower end of the moving body (16) is fitted with a slight play into the recess (23b) of the moving body receiver (23).
[0023]
According to the fluid controller of this embodiment, the length of the portion excluding the body (the length of the actuator portion) can be reduced to about half of that of the conventional one, and the fluid controller can be downsized. Can be achieved. Further, in a state in which the lower end surface of the arcuate section in vertical section of the moving body (16) is in contact with the bottom surface of the arcuate cross section of the concave portion (23b) of the moving body receiver (23), the moving body receiver (23) is coil spring (24 ), The moving body (16) of the driving device (5) and the moving body receiver (23) of the connecting means (6) are connected by this upward urging force, and the driving device ( The same effect as in the case where the moving body (16) and the stem (3) of 5) are integrally formed by welding or screws is obtained, and rattling in the axial direction is prevented. When the rotor in the drive device (5) has a screw mechanism, the axial play of the screw generated in the screw portion can be eliminated by the upward urging force. Furthermore, when the moving body (16) of the driving device (5) and the stem (3) are joined by, for example, welding or screws, the axis of the moving body (16) and the stem (3) are integrated. When the center is not protruded, the thrust load is always applied and a problem easily occurs during operation. However, the moving body receiver (23) is connected to the coil spring (24). , The moving body (16) and the moving body receiver (23) move integrally even if the axis of the moving body (16) and the axis of the stem (3) are not joined. As a result, work such as welding and screwing is unnecessary, and there is no misalignment between the axis of the moving body (16) and the axis of the stem (3), and a malfunction does not easily occur because no thrust load is generated. It also has the advantage.
[0024]
FIG. 2 shows a second embodiment of the fluid controller according to the present invention.
[0025]
The fluid controller (1) of this embodiment is different from that of the first embodiment in the connecting means (6) for connecting the stem and the driving device. That is, in this embodiment, in the connecting means (6) between the stem and the driving device, the bottom surface of the recess (23b) of the moving body receiver (23) into which the lower end of the moving body (16) is fitted is made flat. ing. The diameter of the concave portion (23b) is slightly larger than the diameter of the lower end of the moving body (16), and the lower end of the moving body (16) has a slight play and has a small play. In the recess (23b).
[0026]
Other configurations of the second embodiment are the same as those of the first embodiment, and the same components are denoted by the same reference numerals and description thereof is omitted.
[0027]
The fluid controller of this embodiment has the same effect as that of the first embodiment although the bottom surface of the recess (23b) of the moving body receiver (23) is flat. That is, the length of the portion excluding the body (the length of the actuator portion) can be reduced to about 比 べ as compared with the conventional one, and the fluid controller can be reduced in size. Further, with the lower end surface of the arcuate vertical section of the moving body (16) abutting against the bottom surface of the recess (23b) of the moving body receiver (23), the moving body receiver (23) is turned upward by the coil spring (24). The moving body (16) of the driving device (5) and the moving body receiver (23) of the connecting means (6) are connected by this upward urging force, and The same effect as when the moving body (16) and the stem (3) are integrated by welding or screws is obtained, and rattling in the axial direction is prevented. In addition, when the rotor in the drive device (5) has a screw mechanism, it is possible to eliminate the axial play of the screw generated in the screw portion. Furthermore, when the moving body (16) of the driving device (5) and the stem (3) are joined by, for example, welding or screws, the axis of the moving body (16) and the stem (3) are integrated. If the centering is difficult and the centering is not done, the thrust load is always applied. Therefore, a problem is likely to occur during the operation. However, the moving body receiver (23) is connected to the coil spring (24). , The moving body (16) and the moving body receiver (23) move integrally even if the axis of the moving body (16) and the axis of the stem (3) are not joined. As a result, work such as welding or screwing is unnecessary, and there is no misalignment between the axis of the moving body (16) and the axis of the stem (3), and no malfunction occurs because no thrust load is generated. It also has the advantage.
[Brief description of the drawings]
FIG. 1 is a sectional view showing a first embodiment of a fluid controller according to the present invention.
FIG. 2 is a sectional view showing a second embodiment of the fluid controller according to the present invention.
[Explanation of symbols]
(1) Fluid controller (2) Body (2a) Fluid inflow passage (2b) Communication passage (2c) Fluid outflow passage (3) Stem (4) Holder (5) Linear stepping motor (drive unit)
(6) Connection means between stem and drive device (16) Moving body (23) Moving body receiver (23b) Recess (24) Compression coil spring (elastic member)

Claims (3)

A body having a fluid inflow passage, a fluid outflow passage, and a communication passage communicating the two passages, and a stem having a distal end that blocks or opens the communication passage by being moved vertically in a vertical passage including the communication passage; A fluid controller comprising a drive for moving the stem up and down,
The driving device is a linear drive stepping motor having a moving body that moves up and down, and a moving body receiver that receives a lower end of the moving body of the driving device is provided at an upper end of the stem, and the moving body receiver is directed upward by an elastic member. A fluid controller characterized in that the fluid controller is brought into contact with the moving body from below with an upward load being constantly applied by being biased to the moving body. 2. The fluid controller according to claim 1, wherein a lower end surface of the moving body of the driving device is formed in an arc shape in a vertical section, and a concave portion is formed in an upper end portion of the moving body receiver, into which the lower end of the moving body is fitted. 3. The fluid controller according to claim 2, wherein the bottom surface of the recess has an arc-shaped cross section.

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