JP2009162384A - Flow control valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flow control valve capable of reducing an influence of a change in the viscosity of a control fluid. <P>SOLUTION: The flow control valve includes a sliding shaft 30 and a sliding cylindrical face 21a fitted mutually to slide in the axial directions, and a moving mechanism 40 for moving the sliding shaft. The fluid is controlled between a V-shaped tapered groove 33 formed on a surface of the sliding shaft 30 and the sliding cylindrical face 21a. The V-shaped tapered grooves 33 is shaped to be gradually decreased or increased according to a prescribed function. The sliding shaft 30 of the moving mechanism 40 and the sliding cylindrical face 21a are formed of materials having different thermal expansion coefficients, and the change between flow passages by the temperature change and a flow rate change amount by the change of viscous resistance are canceled with each other. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a control valve that controls the flow rate of a fluid such as liquid or gas, and more particularly to a highly reliable flow rate control valve that can precisely and widely adjust the flow rate and can withstand long-term use.

  Conventionally, a precision needle valve is known as an adjustment valve that can precisely control the flow rate of fluid. FIG. 12 is a structural sectional view showing an outline of a precision needle valve that has been conventionally used. In the needle valve having such a configuration, a shaft (needle) 202 having a tapered shape near the tip is inserted into a cylindrical hole 203 by turning the knob 201, and is provided in the tapered shaft 202 and the housing 204. The size of the ring-shaped gap generated between the hole 203 changes.

  As a result, since the flow path resistance with respect to the fluid flowing in from the fluid inlet 205 and flowing out of the fluid outlet 206 through this gap changes, the flow rate can be adjusted.

  FIG. 13 shows the flow rate adjustment characteristics of such a conventional needle valve. Here, sample b1 to sample b5 show the characteristics of typical conventional needle valves, and show characteristics close to linear characteristics in a predetermined flow rate range. When the valve opening is 10% or less, the flow rate change rate with respect to the rotation angle of the valve operation becomes large and it becomes difficult to set the flow rate. Therefore, it is usually used in the range of 10% to 90% of full scale. Yes. Incidentally, sample a shows the characteristics of the valve of the present invention for reference.

  By the way, as can be seen from the comparison with the sample a, the flow rate adjustment range of the conventional needle valve as shown in FIG. 12 is narrow, and commercially available products range from several types to 20 types or more depending on the flow range for each company. It will be. The valve user has to select an optimum valve from a large number of valves described in the catalog according to the desired flow rate range. For this reason, if the flow rate or fluid resistance range is changed due to a design change, fluid change, etc., or if the prediction or selection of the flow rate is incorrect, purchase a product with a different flow rate range again. It had to be fixed and was uneconomical and inconvenient.

  In addition, with a conventional needle valve that inserts a tapered shaft into the hole, the gap between the tapered shaft and the hole is pressed until it reaches zero, so the surface of the portion wears out and deforms over time, making it impossible to adjust the flow rate. There were drawbacks in that it became stable and the flow rate could not be made completely zero.

  Further, there is a problem that the constituent material expands or contracts due to a temperature change, and as a result, the flow rate changes to cause a flow rate error. That is, in the case of a needle valve that is not temperature-compensated at all, an error due to a temperature change per 1 ° C. is about 0.4%. The error per degree C was improved only to about 0.3%. In almost all applications, it is desirable that this error be small, and for temperature compensation, it is desirable to suppress the error to at least 0.1% per 1 ° C.

  JP 2000-179748 A (Patent Document 1) is a resistance valve for quantitatively distributing or proportionally distributing lubricating oil supplied under pressure in a unitary manner to a number of locations to be lubricated in a machine, In order to provide a novel throttle valve having a high degree of fluid resistance, a female screw is formed on an inner peripheral surface of a hole of a passage member in a mechanism including a resistor for limiting an effective sectional area of a fluid passage. In addition, a male screw that fits into the female screw is formed on the outer peripheral surface of the main part of the resistor, and either one of the female screw or the male screw is cut into a predetermined dimension, and the screw thread A structure of a resistance valve is disclosed in which the cut portion is formed as a fluid passage.

  However, in the structure of this document, if the female screw and the male screw are not engaged with each other without a gap, the fluid flows directly in the axial direction through the gap between the valley and the mountain. For this reason, the male screw and the female screw must have a perfect eye-eye structure, which requires extremely high precision processing, is extremely difficult to manufacture, and is expensive, and the risk of fluid leakage There was also.

  The throttle valve in this document also changes the effective opening area of the screw thread gap as a fluid passage to change the throttle opening, but it did not compensate for the change in flow rate due to temperature change. .

  By the way, the error of many conventional flowmeters is specified in the form of ± E% with respect to the full scale, and measurement at ± E% is possible near the full scale. When trying to measure a flow rate as small as%, the error must be as much as 10 times larger than the reading ± 10 × E%.

  Several decades ago, flow meters called “mass flow meters” or “mass flow meters” have become widespread, and mass flow controllers using these flow meters have been used in today's high-tech industries, including the semiconductor industry. It has become an important technology that supports industry. In the mass flow meter, the error regulation is in the form of ±% of full scale, like the flow meter of other principles. Therefore, the error increases when the flow rate is as small as 10% or less with respect to the full scale.

  In a mass flow meter, the flow rate is measured by applying heat to the fluid and measuring a slight temperature rise. Although it is possible to obtain a signal related to the flow rate, the phenomenon in which the signal is extracted as a sensor is extremely complicated, and there is no clear theoretical formula. Since the physical properties such as thermal conductivity and specific heat differ depending on the fluid, the mass flow meter is often dedicated to one kind of fluid. Some of the internal programs can handle several types of fluids, but in many cases, it has been difficult to use a mass flow meter for air, for example, as a fluid of different gas types such as argon and helium. In addition, even with an area-type flow meter, it is possible to read the flow rate at a position where the sphere in the tapered glass tube balances the gravity and the dynamic pressure of the gas from below, but the flow of fluid before and after the sphere Is complicated, there is no simple theoretical formula, only a coefficient such as “flow coefficient” is introduced and explained, and there is a problem that only one type of fluid can be used with the same flow meter. .

  On the other hand, the present inventor disclosed in Japanese Patent Application Laid-Open No. 2006-138399 (Patent Document 2), a flow rate control valve in which the flow rate does not change even if there is a temperature change, and the flow rate change rate with respect to the rotation angle is constant at any position. In view of the above, a flow control valve including an operation shaft 12, an auxiliary sleeve 18 having a tapered groove 14 formed on the outer peripheral surface, and a housing 20 fitted to the operation shaft and the auxiliary sleeve has been proposed. In this flow control valve, a fluid passage is formed through a tapered groove 14 between one fluid inlet / outlet 22 opened at the other end of the housing and the other fluid inlet / outlet 24 opened at the side of the housing.

  That is, a spiral groove having a regular triangle cross section is provided on the outer periphery of the cylindrical shaft, and the flow rate change is achieved by changing the position of the spiral channel formed when this shaft is inserted into the cylinder. Yes. Then, by changing the depth of the groove exponentially, a very large flow rate change can be obtained.

  However, in the method of this document, there is only one thin groove constituting the flow path, and there is a problem that the flow rate is significantly reduced discontinuously when fine foreign matter enters the flow path. That is, there is a problem that the flow rate suddenly decreases at the foreign matter portion and fine adjustment of the smaller flow rate becomes impossible in the vicinity of the flow rate.

  Thus, when there is only one groove constituting the flow path, if wear powder generated by sliding wear or fine particles that are contained in the fluid and enter from the outside accumulate in the groove of the flow path, the resistance is locally increased. Increases and the flow rate decreases rapidly at that position. FIG. 6 shows an example of characteristics when such a flow control valve is clogged with foreign matter. The sample c2 in FIG. 6 has a step shape with the flow rate being about 50 mL / min at a movement distance of about 7 mm on the horizontal axis (movement distance from the fully closed state of the sliding shaft inside the main body). This is because foreign matter is present in the groove of this portion. The sample c1 has a characteristic when no foreign matter is clogged.

In addition, when the knob for operation is rotated, the sliding shaft with the tapered groove also rotates, so that the sliding surface generates friction powder due to friction with the sleeve having the cylindrical inner surface. There is a drawback that the flow resistance is increased by adhering to the surface.
JP 2000-179748 A JP 2006-138399 A Co-authored by Kobayashi Kiyoshi and Iida Yoshihiro, “New Version Migration”, 22nd edition, Asakura Shoten Co., Ltd., October 1997, p. 30, p. 48 Technical University of Denmark, MIC: Department of Micro and Nanotechnology, Dr. Henric Bruus, TheoreticaL microfluidics, Lecture notes second edition, fall 2005,

  As described above, it is possible to change the flow rate over a wide range, and it is excellent in durability, and it is difficult to cause problems with repeated use. Has long been desired.

  The present invention has been made to solve the above problems, and is a flow rate control valve whose flow rate increases or decreases in a wide range and monotonously according to the rotation of the operation knob. Alternatively, an object of the present invention is to provide a flow rate control valve that does not cause a significant deterioration in characteristics even when foreign matter in the fluid is present in the flow path and that ensures that the flow rate at the deadline is zero.

  Among the above objects, two means have been proposed in order to realize durability in repeated use. The first means is a technique that does not cause a large obstacle in characteristics even if there is a foreign substance, and the second means is means for suppressing the generation of wear powder due to internal friction of the control valve. First, a means for making it difficult to cause a failure due to the presence of the first foreign substance is a plurality of triangular tapered groove fluid passages in which the depth of the valve body gradually increases.

  In other words, the above-mentioned drawbacks were dramatically improved by forming not only one groove but two or more grooves on the outer periphery of the sliding shaft. Since the fluid flows in a bundle of a plurality of grooves, the worst case is that even if one groove is closed, the other grooves flow as flow channels, and the flow rate does not become zero.

  The result of examining this state with a numerical model is shown in the graph of FIG. The horizontal axis in FIG. 7 represents the opening of the valve, and the vertical axis represents the flow rate on a logarithmic scale. This model is a valve having a flow path whose depth is changed exponentially as described in detail below. When the groove is a single sample e1, the valve opening is lowered from 100%. For example, it is assumed that there is a foreign substance at the groove position X where the valve opening degree is 38%, and the flow rate becomes about 1/17 due to the flow path resistance there.

  In that case, even if the valve is further closed, the flow rate is determined by the flow path resistance at the position of the foreign matter, and the flow rate of about 0.25 mL / min remains at about 0.015 mL / min, which is about 1/17 or less. Thus, the flow rate can be adjusted only when the valve opening is about 16%, but there is a disadvantage that the flow rate in the section up to this point cannot be adjusted.

  From there, there is no change in the flow rate until the foreign substance moves out of the fluid resistance section of the tapered groove and the flow resistance becomes 1/17, so that the characteristics are stepped as shown in the sample e1 in the figure.

  Thus, it can be seen that the flow rate of the sample e1 having one groove in FIG. 7 cannot be set at all between about 18% to 38% of the valve opening. In sample e2 having two grooves, the flow rate of the second flow path maintains the original characteristics even if foreign matter enters one groove, so the characteristics are greatly improved as a combined flow rate. I understand. Three samples e3 are further improved. It can be seen that the samples e2 and e3 are not inferior even when compared with the sample e0 showing the ideal characteristics. If there are a plurality of grooves, the fluid flows in other flow paths, so even if there is a local decrease in the flow rate, the apparent change in flow rate as a whole does not become serious.

  In this example, as an extreme case, a very large foreign object is clogged in one place and the flow rate becomes 1/17. However, in practice, the foreign object is often smaller, so use multiple grooves. Therefore, even if a foreign object enters, the actual obstacle can be suppressed to a very small level. Although it was actually improved to have three grooves and the rotation of the knob, which will be described in detail below, was not transmitted to the sliding shaft, it was evaluated after obtaining and evaluating the data after the endurance test. Even after the endurance test that was reciprocated 100 times or more until fully opened, it was found that almost the initial characteristics were maintained.

  Next, means for suppressing the generation of wear powder due to sliding inside the valve will be described. The wear volume is proportional to the contact pressure and the friction distance according to the Archard's law when the constituent material is determined. Therefore, it is desirable to make the relative movement of the sliding surface as small as possible. Therefore, when the sliding shaft is moved relative to the cylindrical inner peripheral surface of the sleeve, the rotation of the operation shaft is not transmitted, but only the straight movement is transmitted.

  There is a conventional needle valve that advances and retreats the taper shaft, and the rotary motion of the operation shaft is a straight motion. These have a structure in which rotation is restricted inside and only a straight movement is possible. In this case, there is a drawback that the structure becomes complicated and the manufacturing cost increases. In the present invention, the operating shaft and the central axis of the valve are connected so that rotational torque is not transmitted, the rotation of the sliding shaft is not restricted, and the rotation is minimized by the resistance of the O-ring for sealing, etc. It is to become.

  As a result, even if the rotation is not constrained, the sliding shaft actually operates with little rotation, so that the mechanism is greatly simplified. The O-ring for sealing may be at one place, but two or more O-rings may be used to further improve the sealing performance. In this case, the effect of preventing the rotation of the sliding shaft is also increased. Achieved and convenient.

  FIG. 13 shows the relationship between the valve opening degree and the flow rate of the tapered groove type flow rate control valve of the present invention and the conventional needle valve (flow rate control valve) of the type that advances and retreats the tapered shaft. As can be seen from FIG. 13, the flow rate adjustment valve of invention sample a can be adjusted with a single valve in a wider flow range than the five types of valves from sample b1 to sample b5.

  As described above, since the flow rate control valve of the tapered groove type can adjust the flow rate in a very wide range, the valve selection operation is very easy and the possibility of erroneous selection is reduced. In addition, since the flow rate can be adjusted in a wide range with one valve, conventionally, even when a plurality of valves must be used in combination, the effect that only one valve is required is exhibited.

  In addition, by making the number of grooves through which the fluid flows into a plurality, it becomes possible to adjust what has become impossible for the flow rate to be adjusted only by one small foreign substance entering the groove. Also, the generation of fine powder due to sliding wear in the valve could be dramatically reduced by adopting a connecting part that does not transmit rotational torque.

  Furthermore, another structure of the present invention, in order to ensure that the flow rate is zero by the deadline, O-rings are mounted at two locations on the sliding shaft, and a structure that can reliably seal between the sleeves is provided.

  Although not shown in the drawings, the diameter of the shaft on the side near the tip of the sliding shaft having a deep taper groove is reduced in the diameter on the tip side in the same manner as the conventional tapered shaft type needle valve. In this way, the maximum flow rate can be further increased. That is, by using the conventional taper shaft method for the large flow rate region and the taper groove method for the medium and small flow rate regions, it is possible to adjust the flow rate in a wider range than in the case of the spiral alone.

（８）
前記移動機構の駆動軸と摺動円筒面とを、互いに熱膨張係数の異なる材料により構成し、
前記テーパー溝は、温度変化による前記材料の膨張または収縮で前記テーパー溝の流体通路の区間が変化して流量が変化する量と、温度変化による流体の粘性抵抗の変化で流量が変化する量とが打ち消し合うような形状に形成されている流量調節弁。
（２） 前記テーパー溝は、スパイラル状に形成されている上記（１）の流量調節弁。
（３） 前記移動機構は、回転動作を直線状の動作に変換するためのねじ部を有し、軸を回転させることにより前記摺動軸を移動させる操作軸と、前記操作軸の回転動作が前記摺動軸に伝達されないように両者を連結する連結部とを有する上記（１）または（２）の流量調節弁。
（４） 前記移動機構は、制御可能な直線状の動作を行う駆動機構により構成されている上記（１）〜（３）のいずれかの流量調節弁。
（５） 前記摺動円筒面は、本体に形成された縮径部により構成されている上記（１）〜（４）のいずれかの流量調節弁。
（６） 前記摺動円筒面は、本体とは別に設けられた補助スリーブにより構成されている上記（１）〜（５）のいずれかの流量調節弁。
（７） 前記摺動軸には、締め切り用のシール部材が設けられている上記（１）〜（６）のいずれかの流量調節弁。
（８） 互いに軸方向に摺動可能に嵌合された摺動軸および摺動円筒面と、前記摺動軸を軸方向に移動させる移動機構とを有し、
前記摺動軸および摺動円筒面の少なくとも一方の摺動面にはその特定領域が流体通路となる複数のテーパー溝が形成され、このテーパー溝は長さ方向に沿って流路抵抗が漸減または漸増する形状になっている流量調節弁。
（９） 前記テーパー溝は、流量抵抗が所定の関数に従って漸減または漸増するように形成されている上記（８）の流量調節弁。 That is, the above object can be realized by the following configuration of the present invention.
(1) having a sliding shaft and a sliding cylindrical surface that are slidably fitted to each other in the axial direction, and a moving mechanism for moving the sliding shaft in the axial direction;
A plurality of tapered grooves whose specific regions serve as fluid passages are formed on at least one sliding surface of the sliding shaft and the sliding cylindrical surface. The tapered grooves have an equilateral triangle cross section, and extend along the length direction. The depth gradually decreases or increases according to the function,
The function is the following formula (8) representing the resistance R from the section xL to x when the fluid having the viscosity coefficient μ flows through the channel having the total length L.

(8)
The drive shaft of the moving mechanism and the sliding cylindrical surface are made of materials having different coefficients of thermal expansion,
The taper groove has an amount of change in flow rate due to a change in fluid passage section of the taper groove due to expansion or contraction of the material due to temperature change, and an amount of change in flow rate due to change in fluid viscosity resistance due to temperature change. A flow control valve that is shaped to cancel each other out.
(2) The flow rate control valve according to (1), wherein the tapered groove is formed in a spiral shape.
(3) The moving mechanism has a screw portion for converting a rotation operation into a linear operation, and an operation shaft that moves the sliding shaft by rotating the shaft, and a rotation operation of the operation shaft. The flow rate control valve according to (1) or (2), further including a connecting portion that connects the two so as not to be transmitted to the sliding shaft.
(4) The flow control valve according to any one of (1) to (3), wherein the moving mechanism is configured by a drive mechanism that performs a controllable linear operation.
(5) The flow regulating valve according to any one of (1) to (4), wherein the sliding cylindrical surface is configured by a reduced diameter portion formed in the main body.
(6) The flow regulating valve according to any one of (1) to (5), wherein the sliding cylindrical surface is configured by an auxiliary sleeve provided separately from the main body.
(7) The flow rate control valve according to any one of (1) to (6), wherein a seal member for closing is provided on the sliding shaft.
(8) a sliding shaft and a sliding cylindrical surface that are slidably fitted to each other in the axial direction, and a moving mechanism that moves the sliding shaft in the axial direction;
A plurality of tapered grooves whose specific regions serve as fluid passages are formed on at least one of the sliding shaft and the sliding cylindrical surface, and the taper grooves gradually decrease the flow resistance along the length direction. A flow control valve with a gradually increasing shape.
(9) The flow rate control valve according to (8), wherein the tapered groove is formed such that the flow resistance gradually decreases or gradually increases according to a predetermined function.

According to the present invention, according to the rotation of the operation knob, the flow rate can be increased or decreased in a wide range and monotonously, internal wear is unlikely to occur, and wear powder or foreign matter in the fluid should be present in the flow path. However, it is possible to provide a flow rate control valve that does not cause significant deterioration in characteristics and that can reliably reduce the flow rate to zero by the deadline.
In addition, since the rotation of the operation shaft is not transmitted to the sliding shaft, internal wear hardly occurs.
In addition, since the flow rate change rate with respect to the rotation angle can be designed and manufactured at any position of the valve opening degree, the flow rate can be easily set.
Moreover, since a very wide flow rate range can be adjusted with one valve, selection and management of the valve are easy.
Furthermore, since commercially available parts can also be used, it can be realized at low cost and is convenient for maintenance.

  The flow control valve of the present invention includes a sliding shaft and a sliding cylindrical surface that are closely opposed to each other so as to be slidable in the axial direction, and a moving mechanism that moves the sliding shaft in the axial direction. And at least one sliding surface of the sliding shaft and the sliding cylindrical surface is formed with a plurality of tapered grooves whose specific flow areas serve as fluid passages, the tapered grooves being in the length direction, that is, one end of the fluid passage. The flow path resistance gradually decreases or gradually increases along the other end direction.

  As described above, by adjusting the flow rate of the fluid using the tapered groove, it is possible to accurately adjust the flow rate over a wide range. Further, by selecting appropriate materials for the sliding shaft and the sliding cylindrical surface and adjusting the shape of the tapered groove, the error due to temperature change can be made extremely small.

  In the conventional variable throttle, as shown in FIG. 12, a tapered cylindrical rod is inserted into the round hole, and the size of the annular gap is gradually reduced to increase the flow path resistance. On the other hand, in the flow rate control valve of the present invention, the size of the cross section of the flow path constituted by the grooves is gradually reduced. Sliding that is a hole with an inner diameter in close contact with the outer peripheral surface is provided with a groove such as a regular triangle on the outer peripheral surface of the cylindrical sliding shaft or the inner peripheral surface of the hole. Insert into the cylindrical surface. Then, the depth of the groove is formed so as to gradually increase or decrease, and one of the areas of the sliding shaft and the sliding cylindrical surface and the other partial area are in close contact with each other, thereby specifying the groove. Only the groove portion of the region is a flow path. For this reason, the specific region is moved by the movement of the sliding shaft, the fluid resistance of the groove is changed, and the flow rate can be adjusted.

  This groove can be formed arbitrarily with high accuracy in accordance with the required rate of change of fluid resistance, and processing is relatively easy. Further, by setting the length and size of the groove arbitrarily, the variable range and change rate can be changed arbitrarily and over a wide range. Therefore, the flow rate can be adjusted with high accuracy over a wide range with a simple structure. The number of taper grooves is not particularly limited as long as it is more than one and is a plurality of taper grooves, but three or more are preferable from the viewpoint of preventing deterioration of characteristics. However, if the number increases too much, the manufacturing cost increases, making it difficult to reduce the size and deteriorating accuracy. For this reason, if it is a normal use form, 5-6 or less is preferable.

  Next, the configuration of the present invention will be described with reference to the drawings. FIG. 1 is a partial cross-sectional view showing the principle of the flow control valve of the present invention. In FIG. 1, fluid enters from the fluid inlet 301 of the housing 321 and exits from the fluid outlet 302. A sliding shaft (hereinafter referred to as “sliding shaft”) 330 in which a tapered groove is formed is partially blocked by the sliding cylindrical surface of the reduced diameter portion 321 a provided on the inner peripheral surface of the housing 321, and the remaining portion. Is exposed.

  Since the sliding surface on the outer periphery of the sliding portion 332 of the sliding shaft 330 is in a close fitting state with the sliding cylindrical surface of the reduced diameter portion 321a at the center of the housing 321, the fluid flowing in from the inlet 301 is , Flows out of the outlet 302 through the tapered groove 333 of the sliding shaft 330. By moving the sliding shaft 330 in the axial direction via the guide portion 331, the size of the triangular groove of the tapered groove 333 is changed, and as a result, the flow path resistance is changed, so that the flow rate can be changed.

  FIG. 2 is a three-dimensional view of a channel having a triangular cross section and a groove depth that varies geometrically. The groove 333 in FIG. 1 is obtained by processing a groove 403 having an equilateral triangle whose depth geometrically changes as shown in FIG. 2 into a cylindrical surface. The fluid flows into the equilateral triangular groove from the fluid inlet 402 and flows out from the fluid outlet 401. As the sliding shaft 330 in FIG. 1 moves in the axial direction, the section 404 moves and the flow path resistance changes.

  According to the Hagen-Poiseuille law, the flow rate in a laminar circular pipe is usually proportional to the fourth power of the diameter. Even in the case of a non-circular channel, it is known that the flow rate is proportional to the fourth power of the equivalent diameter due to the “hydraulic equivalent diameter” corresponding to the shape of the channel. (See Non-Patent Document 1) Therefore, when the depth of the triangular groove is reduced to 1/10, the flow rate is reduced to the negative fourth power of 10, that is, 1 / 10,000. By reducing the depth of the triangular groove exponentially and forming it on the outer periphery of the shaft, the flow rate can be reduced exponentially.

  For example, considering the flow rate in a section with an average groove depth of 1.5 mm and a groove depth of 0.15 mm, which is an average of 1/10, the depth is 1/10. Becomes 1 of 10,000. That is, when the groove depth is an average of 1.5 mm and the flow rate is 1 L / min, the groove depth is 0.1 mL / min in the section where the groove depth is 0.15 mm. To be exact, it is necessary to perform integral calculation for the section that is an exponential function with the pipe resistance of the triangular channel.

Here, the method for obtaining the fluid resistance using Hagen-Poiseuille's law will be described in more detail. The Hagen-Poiseuille equation is described in general fluid engineering textbooks, etc., so please refer to them for details. Here, the flow rate Q in a laminar flow state when a fluid having a viscosity coefficient μ flows in a circular tube having a radius r and a length L with a differential pressure Δp is expressed by the Hagen-Poiseuille equation (1) below. The resistance R of the road is expressed by equation (2).
Q = RΔp (1)
R = 8 μL / πr ⁴ (2)

  Next, the case where the shape of the channel is an equilateral triangle having a length a of one side will be considered. The flow rate in the triangular channel is the "Lecture notes second edition, fall 2005, TheoreticaL microfluidics", p35 (Technical University of Denmark) In Section 2.4.4 of Non-Patent Document 2), the channel having a triangular cross section shown in Fig. 2.6 (c) is studied. The following equation (3) is derived by obtaining the flow path resistance R according to the above from the equation 2.37 for obtaining the flow rate Q shown in this section.

（３）
ここで、正三角形の高さをｈとすると、

(3)
Here, if the height of the equilateral triangle is h,

（４）
(3) (4)式より、高さの正三角形流路の抵抗は次式になる。

(4)
(3) From the equation (4), the resistance of the regular equilateral triangular channel is as follows.

（５）

(5)

Next, the channel resistance when the depth gradually decreases in the longitudinal direction is obtained.
Considering the case where the depth of the equilateral triangular groove decreases exponentially in the longitudinal direction, assuming that L = x, the groove depth is expressed by the following equation.

（６）
(5)、(6)式から、長手方向のある微小区間での抵抗は

(6)
From equations (5) and (6), the resistance in a minute section in the longitudinal direction is

（７）
となり、長手方向に、区間ｘ−Ｌからｘまでの抵抗は、上式を積分すると、

(7)
In the longitudinal direction, the resistance from the section xL to x is obtained by integrating the above equation:

（８）
となる。

(8)
It becomes.

  This equation (8) is a calculation formula for obtaining the fluid resistance of a fluid when a fluid having a viscosity coefficient μ flows through a channel having a regular triangular cross section whose depth gradually decreases in the longitudinal direction and a total length of L. is there. From this equation, the relationship between the flow path length L and the fluid μ and the fluid resistance / flow rate can be calculated.

  Thus, although the cross-sectional shape of the tapered groove can be obtained according to the above formula, the groove shape may be determined based on data or the like verified with a model in which the groove is actually formed. The specific shape of the cross-section of the groove may be adjusted to the optimum value according to the required flow control valve performance, specifications, specification environment, fluid type, and the like.

  In the present invention, the length of the sliding shaft and the sliding cylindrical surface is determined so that a partial region of the tapered groove constitutes the flow path. In other words, when the sliding shaft slides on the sliding cylindrical surface, the region of the portion where the sliding shaft and the sliding cylindrical surface are in close contact changes, and only the tapered groove in the specific region in this portion is the flow path. It becomes. And if the groove part of this specific area | region changes, since fluid resistance also changes, flow volume is adjusted. That is, since a specific fluid resistance corresponds to a specific position of the groove, the fluid resistance also changes if the position of the groove constituting the flow path is changed.

  As shown in FIG. 1, the area where the sliding shaft and the sliding cylindrical surface are in close contact with each other may be configured such that one is shorter than the other and is in close contact / fitting with only part of the other. Alternatively, the structure may be such that the entire end portion gradually contacts and fits from the close contact / fit state. Here, “contact / fitting” means that the outer peripheral surface of a cylindrical or columnar sliding shaft is in close contact with the sliding cylindrical surface, which is the inner peripheral surface of the cylindrical housing, and there is no fluid other than the taper groove. An area that cannot exist. Therefore, the portion that determines the fluid resistance of the entire groove is the portion corresponding to the open end where the sliding shaft moves from the region where the sliding shaft is in close contact / fitting to the portion that is not in close contact / fitting. The fluid resistance is the larger side. The size and length of the sliding shaft and the sliding cylindrical surface may be adjusted to the optimum values according to the performance of the groove to be formed and the flow rate control valve, specifications, specification environment, fluid type, and the like.

  The cross-sectional shape of the tapered groove is not limited to the above example, and any shape can be selected. That is, any shape such as a quadrangle, a triangle, or a semicircle may be used as long as the fluid resistance can be gradually increased or decreased according to the above formula. However, considering the ease of processing and the ease of work for calculating the fluid resistance, the above equilateral triangle is most preferable. In addition, the taper groove may be formed in any shape in the longitudinal direction, that is, from one end to the other end of the flow path, and may be linear, spiral, zigzag, or meandering. From the standpoint of cost and prevention of clogging, a linear shape is preferred, and when a wide adjustment range is desired, a curved, meandering shape such as a spiral shape is preferred. The spiral is recommended as a shape that can be easily processed. Further, by forming a male screw and a female screw on the sliding shaft and the sliding cylindrical surface, and removing a part of the screw, for example, a part of the thread of the male screw, the valley of the female screw may form a groove. Good.

  The material of the sliding shaft and the sliding cylindrical surface is not particularly limited, and a material usually used for a flow rate control valve may be used. Further, it may be optimized according to the required flow control valve performance, specifications, specification environment, fluid type, and the like. From the viewpoint of chemical resistance, ease of processing, temperature characteristics, and the like, fluorinated ethylene resin, nylon resin, and the like are also preferable, and nylon 66, tetrafluoroethylene resin, and trifluorinated ethylene resin are particularly preferably used. Further, the constituent materials such as the main body and the operation shaft may be made of a metal such as brass or stainless steel.

  The flow rate control valve of the present invention can perform positive temperature correction by setting the material and groove structure. The viscosity of the gas increases with increasing temperature, and the flow resistance of the gas increases. For this reason, the flow rate of the gas flowing through the fluid control valve decreases as the temperature rises. On the other hand, when the temperature rises, if the length of the fluid passage is shortened to reduce the gas flow resistance, the gas flow rate can be increased.

  Further, the viscosity of the liquid decreases with increasing temperature, and the flow resistance of the liquid becomes small. For this reason, the flow rate of the liquid flowing through the fluid control valve increases as the temperature rises. On the other hand, when the temperature rises, if the length of the liquid passage is lengthened to increase the flow resistance of the liquid, the liquid flow rate can be reduced.

  In this way, the viscosity of the gas and the liquid has the opposite properties to the temperature change, but the flow control valve that does not change the flow rate even if there is a temperature change by appropriately performing the reverse correction operation. It is possible to obtain.

  That is, if the shape of the groove is set so that the change in flow rate due to the change in the section (position) of the fluid passage of the groove due to temperature change cancels out the change in flow rate due to the change in the fluid's viscous resistance. Good. Even if the length of the fluid passage of the groove remains constant, the flow resistance can be changed because the depth of the groove changes if the section (position) that becomes the resistance element is changed. In this case, the effect of eliminating the temperature dependence of the flow rate can be obtained.

Specifically, when the cross-sectional shape of the tapered groove is an equilateral triangle whose depth exponentially decreases along the longitudinal direction, the drive shaft or operation shaft of the moving mechanism that moves the sliding shaft is made of metal, etc. When the sleeve and the material constituting the main body are made of a resin material, a difference in thermal expansion coefficient occurs between them. For example, the difference in thermal expansion coefficient between brass and nylon resin is 7 × 10 ⁻⁵ / ° C. Moreover, the kinematic viscosity coefficient μ of air becomes 1.73 times as the temperature rises from 0 degrees Celsius to 100 degrees Celsius. From the above equation, when the kinematic viscosity coefficient increases 1.73 times, the flow rate decreases to 1/73. On the other hand, when the temperature rises from 0 degrees Celsius to 100 degrees Celsius, a relative displacement between the operation shaft and the housing in the fluid passage portion occurs. At this time, the fluid passage by the tapered groove moves relatively, and the fluid resistance in the flow path decreases. Thus, temperature compensation is performed by setting the shape of the groove to cancel the increase in the kinematic viscosity coefficient.

  The temperature compensation of the flow rate uses the longitudinal displacement difference due to each thermal expansion of the housing and the operating shaft of the moving mechanism, but the portion in contact with the outer surface of the sliding cylindrical surface having the tapered groove, that is, the sliding shaft The sliding cylindrical surface portion, that is, the portion provided with the tapered groove, that is, the housing is preferably made of a material having the same thermal expansion coefficient. In addition, an auxiliary sleeve may be provided when the material of the main body is different. By doing so, it is possible to prevent the gap between the two from expanding in the radial direction and the flow rate to change greatly, or the gap from being excessively reduced in the radial direction to prevent the operation shaft from moving.

  Next, as an application example of the present invention, a method of determining the dial position at a specific flow rate by one-point calibration when the viscosity coefficient of the fluid is unknown will be described.

  There are cases where it is desired to avoid the complexity of calculating the viscosity coefficient in a fluid whose viscosity coefficient is unknown or a mixture of two or more of gas mixtures. In such a case, by measuring the flow rate at a certain dial rotation position under a certain pressure condition, the flow rate measured at that dial position is derived and “one-point calibration” is performed, so that the rotation position of the dial is Can be determined.

  Even if the pressure condition and / or viscosity are unknown, if the flow rate at a certain dial speed is known, as long as the differential pressure and the viscosity coefficient of the fluid do not change, the other valve dial positions This is because the flow rate is proportional and is uniquely determined. With this “one-point calibration” method, even if you have only a narrow range of flowmeters, even if the flow rate is outside the measurement range of the flowmeter, the error is “same” as the flowmeter used. The flow rate can be set.

  Even if the viscosity coefficient changes depending on the temperature and pressure, a wide range of flow rates can be set for any fluid as long as the flow is a viscous flow by using the above-described “one-point calibration” method. A wide range of flow rates can be set according to the accuracy expected according to the flow rate accuracy calibrated at one point.

  When you want to set a wide range of flow rates with high accuracy, measure the flow rate near the full scale where the accuracy of the mass flow meter is good, and determine the dial position. Until, it is possible to set the flow rate at the dial position.

  Next, more specific embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 3 is a longitudinal sectional view showing the configuration of the first example of the flow rate control valve according to the embodiment of the present invention. The flow rate adjusting valve includes a main body 10, a sleeve 20, a sliding shaft 30, a moving mechanism 40, a knob 50, O-rings 61 to 65, and the like.

  The knob 50 is operated when adjusting the flow rate of the flow control valve, and is fixed to the operation shaft 42 of the moving mechanism 40. The moving mechanism 40 connects the operating shaft 42 and the sliding shaft 30 so that the rotation of the operating shaft 42 is not transmitted to the operating shaft 42 that moves the sliding shaft 30 in the axial direction by rotating the shaft by the knob 50. The connection part 41 is comprised. The operation shaft 42 is screwed with the screw portion 10 a of the main body 10 via the screw portion 43.

  As shown in FIG. 4, the connecting portion 41 includes a cap nut 41 a, a washer 41 b, a child screw 41 c, a long nut 41 d, and an adhesive 41 e, so that the rotation of the operation shaft 42 is not transmitted to the sliding shaft 30. 42 and the sliding shaft 30 with a taper groove are connected. The operation shaft 42 and the cap nut 41a are fixed so that they cannot be rotated with each other, for example, by screwing a screw part. The connecting portion 41 is limited to the illustrated example as long as the operating shaft 42 and the sliding groove 30 with the tapered groove are connected so that the rotational torque of the operating shaft 42 is not transmitted to the sliding shaft 30. Other known mechanical structures may be used.

  The female screw 41c has its head held in the cap nut 41a, and the legs are screwed and bonded to the long nut 41d of the 41d through the through hole of the cap nut 41a. Further, the long nut 41d is slid It is press-fitted into the screw hole of the shaft 30 and fixed with an adhesive 41e. A washer 41b having a low frictional resistance such as a fluoroethylene resin is sandwiched between the head of the core screw 41c and the cap nut 41a and between the cap nut 41a and the long nut 41d. The accompanying rotation of the cap nut 41a is hardly transmitted to the child screw 41c. Note that some of these members may be omitted.

  The sliding shaft 30 includes a guide part 31, a sliding part 32, a tapered groove 33, and a holding part 34 shown in FIG. The guide portion 31 is connected to the child screw 41c through the screw hole of the upper long nut 41d, two O-ring grooves are provided on the outer peripheral portion, and the outer peripheral portion is axial along the inner surface of the main body 10. It is possible to move to.

  Slide shaft seal O-rings 61 and 62 are attached to the two O-ring grooves, and a shut-off O-ring 63 is attached to a stepped portion at the center. In the sliding portion 32, the depth for forming the fluid passage in the outer peripheral portion is gradually reduced or gradually increased along the length direction, and a tapered groove 33 formed of a plurality of parallel grooves is formed. A holding portion 34 for attaching a shut-off O-ring 64 is provided near the tip of the sliding shaft 30 following the sliding portion 32.

  The sleeve 20 has a shape in which one end (top) of the cylindrical shape is open and the other end (bottom) is closed, and is attached to the inside of the main body 10 from the opposite direction to the sliding shaft 30, that is, from below. A sliding cylindrical surface 21a formed on the inner periphery of the sleeve cylindrical portion 21 is fitted to the sliding shaft 30 so as to be slidable in the axial direction.

  An O-ring groove is provided in the outer diameter portion of the central portion in the longitudinal direction of the sleeve 20, and an O-ring 65 is provided in the O-ring groove so as to be sealed on the inner peripheral surface of the main body 10. , Prevents the fluid from leaking from the inlet side to the outlet side. In the step hole portion of the sleeve hole bottom 23 below the center portion of the sleeve 20, in order to guide the fluid flowing from the fluid passage formed by the tapered groove 33 to the outlet 14 of the main body 10, the outer diameter is increased in the radial direction. A sleeve outlet hole 24 is provided.

  Here, the fluid passage formed by the tapered groove 33 is a portion of the entire length of the tapered groove 33 in which the sliding cylindrical surface 21 a on the distal end side of the sleeve 20 is fitted with the sliding portion 32 of the sliding shaft 30 ( This corresponds to a portion where the opening surface of the tapered groove 33 is closed by the reduced diameter portion 321a in FIG.

  Further, a fluid that flows from the inlet 11 of the main body 10 and passes through the inlet bottom hole 12 is formed by the tapered groove 33 between the outer peripheral surface of the sleeve cylindrical portion 21 and the inner peripheral surface of the main body 10. A flow path space for leading to the fluid passage is formed.

  Next, the operation of the flow control valve in FIG. 3 will be described. The fluid flowing in from the fluid inlet 11 of the main body 10 passes through the inlet bottom hole 12 and the flow path space between the outer peripheral surface of the sleeve cylindrical portion 21 and the inner peripheral surface of the main body 10, and is a taper composed of three grooves. The fluid passes through the portion of the fluid passage formed by the groove 33, passes through the sleeve hole bottom 23 and the sleeve outlet hole 24, and then flows out from the fluid outlet 14. By rotating the knob 50 forward or backward, the sliding shaft 30 is reciprocated in the axial direction with respect to the main body body 10, thereby changing the size of the tapered groove 33 and adjusting the flow rate.

  When the operating shaft 42 is rotated with the knob 50, the sliding shaft 30 moves in the longitudinal direction which is the vertical direction of the drawing together with the operating shaft 42, and the outer surface of the sliding portion 30 having the tapered groove 33 is the sliding cylinder of the sleeve 20. It slides along the reduced diameter portion of the surface 21a. When the operation shaft 42 is rotated, the sliding shaft 30 moves in the longitudinal direction without following the rotation. Details of the operation will be described below.

  A connecting portion 41 is interposed between the knob 50 and the sliding shaft 30 to prevent the rotation of the knob 50 from being transmitted to the sliding shaft 30. When the knob 50 is rotated, the operation shaft 42 is screw-coupled via the operation shaft screw portion 43 and the screw portion of the main body body 10, so that the main body body 10 moves forward and backward. Although the sliding shaft 30 is moved forward and backward, since the torque is not transmitted by the connecting portion 41 in the rotation operation of the operation shaft 42, the sliding shaft 30 does not rotate due to the frictional resistance of the O-rings 61 and 62. Move forward and backward.

  As a result, the friction distance between the outer periphery of the sliding shaft 30 and the sliding cylindrical surface of the sleeve cylindrical portion 21 is greatly reduced because there is no rotational direction and only forward / reverse operation. For example, one revolution at 8 mm in diameter is greatly reduced from π · d = 3.14 × 8≈25 mm to a screw pitch = 0.8 mm, which is about 1/31. This dramatically reduces wear.

  By the way, it is desirable that the flow rate adjusting valve has a flow rate of zero in a closed state. For this reason, it is preferable that the sliding shaft has a seal member for closing. Specifically, as shown in FIG. 3, the sliding shaft 30 has an O-ring 64 attached to the tip thereof and an O-ring 63 attached to the center stepped portion, and each is in a valve closed state. The seal functions at two locations, the bottom of the sleeve and the upper end of the sleeve. That is, since double sealing is realized in the deadline state, complete zero flow rate can be realized.

  In the flow control valve shown in FIG. 1, the size of the triangular groove of the fluid passage formed by the tapered groove 33 gradually increases from the fluid inlet toward the fluid outlet, so that foreign matters in the fluid are clogged in the fluid passage. It has a difficult structure. In the above-described embodiment, the number of grooves is three. However, the present invention is not limited to this, and an arbitrary plurality of grooves can be provided.

  Further, these two O-rings 63 and 64 have a good deadline function even if one of them is omitted.

  A flow rate adjusting valve having the structure as shown in FIG. 3 and having three grooves and in which the rotation of the knob is not transmitted to the sliding shaft was created. The flow rate control valve was subjected to an endurance test in which the operation from valve closing to full open was repeated 10 times at a supply pressure of 10 KPa (sample d1), a supply pressure of 100 kPa (sample d2), and a supply pressure of 600 kPa (sample d3). The characteristics of knob rotation speed and flow rate were measured. The results are shown in FIG. In addition, as a comparative sample, a flow rate control valve having one groove and no connection portion that does not transmit rotational torque was prepared, and the same test was performed except that the supply pressure was set to 100 KPa. The initial characteristic sample c1 and the characteristic after the durability test were performed. Sample c2 was measured. The results are shown in FIG.

  As is clear from FIG. 5, the flow rate characteristics of the samples d1 to d3 of the present invention are hardly changed by repeated tests in which the knob is rotated many times under any pressure condition (initial characteristics are omitted). . On the other hand, in the comparative sample of FIG. 6, it can be seen that the foreign matter adheres to the groove in the sample c2 after the durability test, and the flow rate characteristic is stepped. From the above results, according to the flow control valve of the present invention, since the tapered groove is composed of a plurality of grooves, even if wear powder or foreign matter in the fluid is present in the flow path, it has remarkable characteristics. It can be seen that no degradation occurs.

  For one thing, the generation of fine powder due to sliding wear in the valve can be drastically reduced by adopting a structure that does not transmit rotational torque to the connecting part, thereby reducing sliding. This is presumably due to what was possible. Therefore, it can be understood that the deterioration of the flow rate characteristic due to the occurrence of wear can be prevented even during long-term use.

  Further, the nitrogen gas when the dial is opened every 1/25 rotation between the dial rotation speed 5-6, the dial rotation speed 10-11, and the dial rotation speed 15-16 at the supply pressure 100 kPa of the flow rate adjusting valve of the present invention. The flow characteristics are shown in FIGS. Furthermore, FIG. 11 shows the nitrogen gas flow rate characteristics in which repetitive reproducibility is measured when the dial rotation speed is alternately moved at the fifth and tenth rotations under the same pressure condition.

  As is apparent from FIGS. 8, 9, and 10, it can be seen that the dial rotation and the nitrogen flow rate have characteristics that are almost linear at any dial rotation speed position. Further, FIG. 11 shows that stable characteristics are maintained even when the repeated test is performed about 19 times.

  The valve shown in the above embodiment shows the so-called “equal percent” characteristic, and is designed and manufactured so that the flow rate change rate with respect to the rotation angle is almost constant at any position of the valve opening, so the flow rate setting Is easy. Moreover, since a very wide flow rate range can be adjusted with one valve, selection and management of the valve are easy.

  Further, since the flow rate increases or decreases monotonously in a wide range, the valve is easy to operate. In addition, since the rotation of the operation shaft is not transmitted to the sliding shaft, internal wear hardly occurs. In addition, since the tapered groove is composed of a plurality of grooves, even if wear powder or foreign matter in the fluid is present in the flow path, the characteristic is not significantly deteriorated.

  Moreover, by using a part of commercially available parts such as a valve member such as a knob, a main body, and a dial gauge, the part cost can be reduced, and maintenance is convenient.

  In the first and second embodiments, the sliding shaft 30 is moved with respect to the sliding cylindrical surfaces 21a and 121a of the sliding cylindrical portions 21 and 121 by rotating the knob 50. The sliding shaft moving mechanism in is not limited to this. Although not shown, the operating shaft 42 is slidably supported with respect to the sliding cylindrical surface 21a of the sleeve cylindrical portion 21, and the operating shaft is operated by an external reciprocating drive device such as an air cylinder or an electric motor driven linear actuator. The structure which reciprocates 42 in an axial direction is also included.

  In each of the above-described embodiments, the number of grooves is three. However, the present invention is not limited to this, and an arbitrary plurality of grooves larger than one can be provided. In each of the above-described embodiments, the case where the groove has a triangular cross section has been described.

  Moreover, the structure of a connection part is not limited to the structure of an Example, Arbitrary structural means which prevents rotation of an operating shaft from being transmitted to a sliding shaft can be used. The number of O-rings for sliding shaft sealing of the sliding shaft 30 is not limited to two, and any number can be used as necessary.

The present invention can be applied to all fluids such as liquid and gas. Moreover, since the variable adjustment range is extremely wide, a single flow rate adjustment valve can cover a wide range of flow rates, and the application range is wide and versatility is extremely high. Since one type can handle many cases, the mass production effect is high and cost reduction can be expected. In addition, it is useful for medical treatment, semiconductors, precision processing, highly functional materials and the like, and is useful for high chemical resistance, low contamination, and high precision applications.
In addition, the flow path shape of the fluid is relatively flat and smooth, and it has a structure with few protrusions, etc., so it has the characteristics of less turbulent flow and less likely to generate bubbles. Also useful.

  Since the flow control valve of the present invention is basically a viscous flow, the Hagen-Poiseuille equation and measured values are close to each other, and each parameter can be controlled according to a clear theory. Therefore, if the flow rate and the rotational position of the needle valve are measured at one point of arbitrary conditions and the dial rotational position is determined, any fluid can be used as it is as long as the temperature and pressure conditions are maintained.

  In addition, when the pressure changes, the flow rate of the viscous flow is proportional to the differential pressure, and can be easily corrected. By performing the calibration described above, a wide range of flow rates can be set by measuring the volume flow rate at one point, whether it is a mixed gas or a gas whose component is unknown. As described above, the present invention has a very wide application range in the field of fluid flow rate control and is extremely useful in industry.

It is a schematic sectional drawing which shows the principle of operation of the flow control valve using the taper groove | channel of this invention. It is a schematic diagram which shows the example of a shape of the groove | channel of the cross-sectional triangle of the flow control valve using a taper groove. It is a composition longitudinal section showing the 1st example of the flow control valve of the present invention. It is the partial cross section figure which showed the internal structure figure of the connection part. It is a graph which shows the flow volume characteristic after the endurance test of the flow control valve of the present invention. It is a graph which shows the flow volume characteristic before and behind the endurance test of the conventional flow control valve. It is the graph which showed the result of having examined with the numerical model the case where a groove | channel is independent and the case where it is multiple. It is a graph which shows the nitrogen gas flow rate characteristic when a dial is opened every 1/25 rotation between dial rotation speeds 5-6 of the flow control valve of the present invention. It is a graph which shows the nitrogen gas flow rate characteristic when a dial is opened every 1/25 turn between dial rotation speed 10-11 of the flow control valve of the present invention. It is a graph which shows the nitrogen gas flow rate characteristic when a dial is opened every 1/25 rotation between dial rotation speed 15-6 of the flow control valve of the present invention. It is a graph which shows the nitrogen gas flow rate characteristic which measured reproducibility when the dial rotation speed of the sample of this invention was alternately moved to 5th rotation and 10th rotation. It is a cross-sectional view showing the outline of a conventional precision needle valve. It is a graph which shows the flow volume adjustment characteristic of the conventional needle valve.

30 Sliding shaft 21a, 121a Sliding cylindrical surface 33 Tapered groove 40 Moving mechanism 43 Screw portion 42 Operation shaft 41 Connection portion 411 Cap nut 41c Child screw 10 Body body 20 Sleeve 11, 111 Inlet 14,181 Outlet 65,165 O- Ring 110 Different diameter three-way cheese 180 Different diameter bush 170 Cylinder 63, 64 O-ring for deadline

Claims (9)

A sliding shaft and a sliding cylindrical surface that are slidably fitted to each other in the axial direction, and a moving mechanism that moves the sliding shaft in the axial direction;
A plurality of tapered grooves whose specific regions serve as fluid passages are formed on at least one sliding surface of the sliding shaft and the sliding cylindrical surface. The tapered grooves have an equilateral triangle cross section, and extend along the length direction. The depth gradually decreases or increases according to the function,
The function is the following formula (8) representing the resistance R from the section xL to x when the fluid having the viscosity coefficient μ flows through the channel having the total length L.

(8)
The drive shaft of the moving mechanism and the sliding cylindrical surface are made of materials having different coefficients of thermal expansion,
The taper groove has an amount of change in flow rate due to a change in fluid passage section of the taper groove due to expansion or contraction of the material due to temperature change, and an amount of change in flow rate due to change in fluid viscosity resistance due to temperature change. A flow control valve that is shaped to cancel each other out.   The flow rate control valve according to claim 1, wherein the tapered groove is formed in a spiral shape.   The moving mechanism has a screw portion for converting a rotating operation into a linear operation, and an operating shaft that moves the sliding shaft by rotating the shaft, and the rotating operation of the operating shaft is the sliding The flow control valve according to claim 1, further comprising a connecting portion that connects the two so as not to be transmitted to the shaft.   The flow control valve according to claim 1, wherein the moving mechanism is configured by a drive mechanism that performs a controllable linear operation.   The flow regulating valve according to any one of claims 1 to 4, wherein the sliding cylindrical surface is constituted by a reduced diameter portion formed in a main body.   The flow control valve according to claim 1, wherein the sliding cylindrical surface is constituted by an auxiliary sleeve provided separately from the main body.   The flow control valve according to claim 1, wherein a seal member for closing is provided on the sliding shaft. A sliding shaft and a sliding cylindrical surface that are slidably fitted to each other in the axial direction, and a moving mechanism that moves the sliding shaft in the axial direction;
A plurality of tapered grooves whose specific regions serve as fluid passages are formed on at least one of the sliding shaft and the sliding cylindrical surface, and the taper grooves gradually decrease the flow resistance along the length direction. A flow control valve with a gradually increasing shape.   The flow rate control valve according to claim 8, wherein the tapered groove is formed such that a flow resistance gradually decreases or gradually increases according to a predetermined function.

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