JP2022103524A - Motor-operated valve - Google Patents

Abstract

To enable a motor-operated valve to highly accurately control flow volume at low flow volume and to prevent an increase in the amount of leakage from the valve due to the intrusion of foreign matters.SOLUTION: The motor-operated valve comprises: a valve body 11 comprising, in the inside thereof, a valve chest, a valve port 18 and a valve seat 17; a valve element 19 moving forward and backward with respect to the valve seat thereby controlling the passage amount of fluid; a first flow path port communicated with the valve chest via the valve port; a second flow path port communicated with the valve chest; and an electric drive unit driving the valve element, wherein the valve element comprises a needle portion 19a having an inversely conical shape with its diameter gradually smaller toward the valve seat, and adapted to be inserted into the valve port during closing the valve when the valve element is seated on the valve seat, to thereby close the valve port. An angle θ formed by opposed bus bars of the needle portion is 26° or larger and smaller than 45°, and a coating layer 62 mainly formed of fluorine resin (for example, PTFE) is provided on the surface of each of the needle portion and the valve seat. Furthermore, a high-strength base layer (for example, Ni-P plating layer) 61 is provided between the coating layer and each of parent materials 63, 64.SELECTED DRAWING: Figure 3

Description

The present invention relates to an electric valve, and more particularly to a valve body structure of an electric valve having a valve body having an inverted conical needle portion at the tip thereof.

An electric valve that controls the opening degree of a valve by using an electric motor such as a stepping motor has been conventionally used in a refrigerating cycle device equipped with a refrigerant circuit such as an air conditioner, a refrigerating device, and a refrigerating device.

As one of such electric valves, a valve body having a needle portion pointed in an inverted cone shape or an inverted cone shape at the tip is provided, and the needle portion is moved forward and backward so as to be inserted into and removed from the valve opening to open the valve. There is an electric valve that adjusts the degree and controls the flow rate of a fluid (refrigerant or the like) (see, for example, Patent Document 1 below).

Japanese Unexamined Patent Publication No. 2012-197849

By the way, in recent years, with the improvement of the performance of each device constituting the refrigerant circuit and the improvement of the capacity of the refrigerant itself, control at a low flow rate when the flow rate of the refrigerant is small is required.

Here, as one method of performing high-precision control at a low flow rate in an electric valve provided with a needle portion, the angle of the needle portion, that is, the conical or inverted cone-shaped needle portions facing each other (opposing each other). The angle formed by the peripheral surfaces (hereinafter, this angle is referred to as a "valve angle") may be an acute angle.

However, if the valve angle is set to an acute angle, the valve body may bite into the valve seat when the valve is closed, and a phenomenon may occur in which the valve cannot be opened smoothly. More specifically, when the valve angle is smaller than 45 °, the valve body cannot be separated from the valve seat and locks due to the so-called wedge principle (the needle part sticks into the valve opening like a wedge and cannot be pulled out). The phenomenon that the valve cannot be opened occurs.

Further, as the valve angle becomes smaller, foreign matter is more likely to be caught between the valve seat and the valve body, and the valve body and the valve seat are damaged by the biting of the foreign matter, which may cause a problem that the amount of valve leakage increases.

Therefore, an object of the present invention is to enable highly accurate flow rate control at a low flow rate and to prevent an increase in valve leakage due to foreign matter being caught.

In order to solve the above problems and achieve the object, the first electric valve according to the present invention moves forward and backward without rotating with respect to the valve body provided with the valve chamber and the valve opening with the valve seat. It is provided with a valve body that controls the amount of fluid passing through the valve body, a first flow path port that communicates with the valve chamber via the valve port, a second flow path port that communicates with the valve chamber, and an electric drive unit that drives the valve body. , The valve body includes a seating portion having an inverted conical or inverted conical trapezoidal shape whose diameter gradually decreases toward the valve seat, and the seating portion is inserted into the valve opening when the valve seat is seated. An electric valve provided with a needle portion capable of closing the valve opening, the angle formed by the opposing bus wires of the seating portion is set to 26 ° or more and less than 45 °, and either the seating portion or the valve seat is set. Alternatively, both surfaces are provided with a coating layer containing a fluororesin.

In order to improve controllability at low flow rate, it is necessary to reduce the valve angle, that is, the angle formed by the opposing bus wires of the needle part (particularly the seating part that abuts on the valve seat). It has already been mentioned that if the valve angle is smaller than 45 ° in the valve, the needle part may pierce the valve opening like a wedge and the valve body may bite into the valve seat, resulting in a phenomenon in which smooth valve opening cannot be performed. That's right.

Therefore, in the present invention, a coating layer containing a fluororesin is formed on the surface of either one or both of the needle portion (seating portion) and the valve seat. By forming a coating layer containing fluororesin on the surface, the frictional resistance of the needle part inserted and removed from the valve seat (valve port) can be reduced, so even if the valve angle is reduced (even if it is less than 45 °). ) The valve body can be easily pulled out from the valve opening, and the valve body can be prevented from biting into the valve seat.

The lower limit of the valve angle is 26 °, and the reason will be described in detail later in the embodiment.

Further, the second electric valve according to the present invention is a valve body provided with a valve chamber and a valve opening with a valve seat, and a valve body that controls the amount of fluid passing by moving forward and backward while rotating with respect to the valve seat. The valve body is provided with a first flow path port communicating with the valve chamber via the valve port, a second flow path port communicating with the valve chamber, and an electric drive unit for driving the valve body, and the valve body is directed toward the valve seat. It includes a seating portion having an inverted conical shape or an inverted conical trapezoidal shape whose diameter gradually decreases, and is provided with a needle portion that is inserted into the valve opening when the seating portion is seated on the valve seat and can close the valve opening. In the electric valve, the angle formed by the opposing bus wires of the seating portion is set to 26 ° or more and less than 60 °, and the surface of either or both of the seating portion and the valve seat contains a fluororesin. Provided a coating layer.

The first electric valve has a structure in which the valve body moves forward and backward without rotating with respect to the valve seat, but the valve body moves forward and backward while rotating with respect to the valve seat (hereinafter, "" The present invention can also be applied to an electric valve (referred to as "valve rotation structure").

That is, in such a valve body rotation structure, the valve body rotates with respect to the valve material and is brought into contact with and separated from the valve material, so that friction is large, and when the valve angle is about 60 ° (smaller than 60 °), it bites into the valve seat. A phenomenon occurs. Therefore, in the second solenoid valve according to the present invention, the angle formed by the opposing bus wires of the seating portions is set to 26 ° or more and less than 60 ° as described above, and the seating portion is similarly seated as in the first solenoid valve. A coating layer containing a fluororesin is provided on the surface of either one or both of the portion and the valve seat.

Further, the fluororesin is, for example, any one of PTFE, FEP, PFA, ETFE, and modified PTFE.

Further, in a preferred embodiment of the present invention, a base layer having a hardness higher than that of the base material is formed between the coating layer and the base material (the main body portion of the needle portion (valve body) and the main body portion of the valve seat). This is to prevent the valve body and the valve seat from being damaged by the biting of foreign matter. By providing a hard base layer, damage to the valve body and the valve seat due to the biting of foreign matter can be minimized, and valve leakage or an increase in the amount of valve leakage can be prevented.

The base layer is, for example, a Ni-P plating layer. In addition, the thickness of the base layer satisfies the condition of 200 cm ³ / min or less, which is a valve leakage amount generally allowed when the motorized valve is used in a refrigerant circuit, and the cost (processing time) of plating is taken into consideration. It is preferably 10 μm or more and 30 μm or less. This point will be described in more detail later in the embodiment.

The thickness of the coating layer is preferably 5 μm or more and 30 μm or less. The reason for this will also be described in detail later in the embodiment.

According to the present invention, it is possible to control the flow rate with high accuracy at a low flow rate, and it is possible to prevent an increase in the amount of valve leakage due to the biting of foreign matter.

Other objects, features and advantages of the present invention will be clarified by the following description of embodiments of the present invention described with reference to the drawings. In each figure, the same reference numerals indicate the same or corresponding parts.

FIG. 1 is a vertical sectional view showing an electric valve (valve closed state) according to an embodiment of the present invention. FIG. 2 is a vertical sectional view showing an electric valve (valve open state) according to the embodiment. FIG. 3 is an enlarged vertical cross-sectional view of the needle portion and the valve seat of the motorized valve according to the embodiment. FIG. 4 is a diagram showing the relationship between the valve opening degree and the flow rate of the fluid passing through the valve when the valve angle is reduced. FIG. 5 shows an electric valve without a Ni-P plating layer (conventional product), an electric valve with a Ni-P plating layer having a thickness of 5 μm (comparative example), and a Ni-P plating layer with a thickness of 10 μm. For the electric valve (embodiment) and the electric valve (embodiment) provided with a Ni-P plating layer having a thickness of 15 μm, the amount of valve leakage after biting a piano wire having a diameter of 15 μm and a diameter of 130 μm, respectively. It is a diagram which shows the measurement result.

〔overall structure〕
As shown in FIGS. 1 to 3, the electric valve 1 according to the embodiment of the present invention is an electric valve suitable for use for adjusting the fluid flow rate in a refrigeration cycle device such as a heat pump type heating / cooling system. There is a valve main body 11 having a valve chamber 12 and a valve opening 18 and a valve seat 17 that open to the valve chamber 12 inside, and the upper surface portion of the valve main body 11 having an open upper surface is covered and sealed together with the valve main body 11. A can 34 that forms a space, a valve body 19 that controls the amount of fluid passing by moving back and forth (moving up and down) with respect to the valve seat 17, and a first flow path port that communicates with the valve chamber 12 via the valve port 18. 13, a second flow path port 15 communicating with the valve chamber 12, a stepping motor (electrical drive unit) 41 for driving the valve body 19, and a deceleration mechanism (mysterious planetary gear deceleration mechanism) for decelerating the rotation of the stepping motor 41. It includes 54 and a transmission mechanism (screw feed mechanism) 30 that converts decelerated rotational motion into linear motion and transmits it to the valve body 19.

It should be noted that each figure shows two-dimensional coordinates orthogonal to each other representing the vertical and horizontal directions, and the description will be given below based on these directions. Further, in FIGS. 1 and 2, the underlayer and the covering layer (which will be described later with reference to FIG. 3) formed on the surfaces of the valve body 19 and the valve seat 17 are not shown.

A bottomless covered (the bottom surface is opened and the top surface is closed) cylindrical can 34 is joined to the upper end portion of the valve body 11 via a ring-shaped base plate 25, and is attached to the outer circumference (outside) of the can 34. Is provided with a stator 42, while a rotor 47 is rotatably installed on the inner circumference (inside) of the can 34. The rotor 47 and the stator 42 constitute the stepping motor 41.

The stator 42 arranged on the outside of the can 34 includes a yoke 43, a bobbin 44, a coil 45, and a resin mold cover 46. Further, the rotor 47 arranged inside the can 34 is configured by integrally connecting a cylindrical rotor member 47a made of a magnetic material and a sun gear member 48 made of a resin material. A shaft 32 is inserted into the central portion of the sun gear member 48, and the upper portion of the shaft 32 is supported by a support member 33 arranged inside the top of the can 34.

The sun gear 48a of the sun gear member 48 meshes with a plurality of planetary gears 49 rotatably supported by a shaft 50 provided on a carrier 51 placed on the bottom surface of the output gear 53. The upper part of the planetary gear 49 meshes with the annular ring gear (internal tooth fixing gear) 55 attached to the upper part of the cylindrical member 35 fixed to the upper part of the valve body 11, and the lower part of the planetary gear 49 is inside the annular output gear 53. It meshes with the tooth gear 52. The number of teeth of the ring gear 55 and the number of teeth of the internal tooth gear 52 of the output gear 53 are slightly different from each other, whereby the rotation speed of the sun gear 48a is reduced by a large reduction ratio and transmitted to the output gear 53. Tooth. These gear mechanisms (sun gear 48a, planetary gear 49, ring gear 55, and output gear 53) constitute a reduction mechanism (mysterious planetary gear reduction mechanism) 54 that reduces the rotation of the stepping motor 41 described above. ..

A cylindrical bearing member 26 is fitted and inserted into the upper portion of the valve chamber 12 of the valve body 11 and crimped and fixed to the valve body 11. The output gear 53 is in sliding contact with the upper surface of the bearing member 26. Further, the upper portion of the stepped cylindrical output shaft 31 is press-fitted into the center of the bottom portion of the output gear 53, and the lower portion of the output shaft 31 is rotatably inserted into the fitting hole 26a formed in the upper surface portion of the central portion of the bearing member 26. do. Further, the lower end portion of the shaft 32 is rotatably fitted in the upper portion of the output shaft 31.

A female screw portion 27 is formed in the lower portion of the central portion of the bearing member 26, and a male screw portion 29 formed on the outer peripheral surface of the screw drive member 28 is screwed into the female screw portion 27. The bearing member 26 (female screw portion 27) and the screw drive member 28 (male screw portion 29) move the rotary motion supplied from the stepping motor 41 via the screw feed mechanism 30, that is, the reduction mechanism 54, in the vertical direction. It constitutes a transmission mechanism that converts into linear motion and transmits it to the valve body 19.

Here, the output gear 53 rotates at a fixed position in the vertical direction without moving up and down, and is screw-driven in the slit-shaped fitting groove 31a provided at the lower end of the output shaft 31 connected to the output gear 53. A flat driver-shaped plate-shaped portion 28a provided at the upper end portion of the member 28 is inserted to transmit the rotational movement of the output gear 53 to the screw drive member 28 side. When the plate-shaped portion 28a provided on the screw drive member 28 slides in the vertical direction in the fitting groove 31a of the output shaft 31, the output gear 53 moves in the vertical direction when the output gear 53 (rotor 47) rotates. Nevertheless, the screw drive member 28 linearly moves in the vertical direction by the screw feed mechanism 30.

The linear motion of the screw drive member 28 is transmitted to the valve body 19 via a ball-shaped joint 22 including a ball 23 and a ball receiving seat 24 fitted in a fitting hole 19b provided in the center of the upper surface portion of the valve body 19. Be transmitted. The valve body 19 is slidably inserted into (the lower part of) a stepped cylindrical spring case 20 fixed inside the valve body 11, and the valve body 19 is guided by the spring case 20 in the vertical direction. Move to. The screw drive member 28 and the valve body 19 on the drive unit side rotate and slide around the central axis (the central axis of the present invention coincides with the rotation axis of the rotor 47) via the ball 23 (rotational sliding portion). , The rotation of the screw drive member 28 is not transmitted to the valve body 19. Further, a compression coil spring 21 that constantly urges the valve body 19 in the valve opening direction (upward) is provided between the upward stepped surface of the spring case 20 and the downward stepped surface of the upper part of the valve body 19.

Further, the first flow path port 13 is formed on the bottom surface of the valve chamber 12 (valve body 11), the pipe joint 14 is connected to the first flow path port 13, and one side portion of the valve chamber 12 (valve body 11) is connected. The second flow path port 15 is formed, and the pipe joint 16 is connected to the second flow path port 15. Further, the first flow path port 13 communicates with the valve chamber 12 via a valve port (orifice) 18 including a cylindrical inner peripheral surface and a valve seat 17 which is an upper edge portion of the inner peripheral surface. Either one of the first flow path port 13 and the second flow path port 15 is used as an inflow port for flowing the refrigerant into the valve chamber 12, and the other is used as an outflow port for flowing the refrigerant from the valve chamber 12.

[Structure of valve body needle and valve seat]
The valve body 19 has a substantially columnar overall shape, but has an inverted truncated cone shape (or inverted cone shape) whose diameter gradually decreases toward the valve opening 18 so that it can be inserted and removed from the valve opening 18. A needle portion 19a having the above is provided at the lower end. In the valve closed state (see FIGS. 1 and 3) in which the valve body 19 is displaced to the lowermost position, the tapered side surface (seating surface (corresponding to the “seating portion” in the present invention)) of the needle portion 19a is the valve seat. It comes into contact with 17 and closes the valve port 18.

On the other hand, in the valve open state in which the valve body 19 is displaced upward from the valve closed state in FIG. 1, including the fully open state in which the valve body 19 is displaced to the uppermost position (see FIG. 2), the valve body 19 and the valve seat 17 are present. A gap is formed between the and, and the refrigerant flows through this gap. Further, the flow rate of the refrigerant can be adjusted by changing the amount of displacement of the valve body 19 in the vertical direction.

FIG. 3 is an enlarged cross-sectional view showing the needle portion 19a and the valve seat 17 portion (valve opening 18 portion at the center of the bottom of the valve body 11). As shown in this figure, the needle portion 19a forms a base layer 61 on the surface of a metal valve body main body portion 63 such as stainless steel, and further forms a coating layer 62 (on the surface) on the base layer 61. Consists of. Further, the valve seat 17, that is, the valve seat 17, and the bottom of the valve body 11 including the valve port 18 are formed on the surface of the body portion 64 of the valve body made of metal such as brass, and the base layer 61 is similarly to the valve body 19. Is formed, and a covering layer 62 is further formed on the covering layer 62.

Note that FIG. 3 emphasizes the thickness of the base layer 61 and the coating layer 62 for the sake of explanation, and is drawn with respect to the dimensional ratio of each part, that is, the outer diameter of the valve body portion 63 and the inner diameter of the valve opening 18. It does not accurately represent the ratio of the thickness dimension of the base layer 61 and the thickness dimension of the coating layer 62. The hardness of the base layer 61 is preferably higher than that of foreign matter. For example, the foreign matter in the refrigerant circuit is mainly copper powder, iron powder, etc., and therefore has a Vickers hardness (HV) of 500 or more. The one with hardness is good. Further, as the covering layer 62, a layer having a hardness lower than that of the base layer 61 is selected.

[Valve angle and coating layer]
The valve angle θ (angle formed by the opposing bus lines of the needle portion (seat portion) 19a / see FIG. 3) is set to 26 ° in the present embodiment. Further, the coating layer 62 (the coating layer 62 on the valve body 19 side and the coating layer 62 on the valve seat 17 side) is a PTFE layer obtained by PTFE dispersion plating. The PTFE layer by PTFE dispersion plating is a composite plating film having a structure in which PTFE is dispersed in a Ni-P plating matrix in the form of particles. The hardness of the Ni-P plating matrix portion is higher than that of the foreign matter.

FIG. 4 shows the valve opening (lift amount of the valve body 19 (moving distance upward)) and the electric valve 1 when the valve angle θ is 45 ° (broken line) and when the valve angle θ is 26 ° (solid line). It is a diagram showing the relationship with the flow rate of the fluid passing through, but as is clear from this figure, when the valve angle θ is reduced, the increasing tendency of the flow rate with respect to the increase in the valve opening becomes gentle, and when the flow rate is low. More accurate control is possible. Therefore, in the present embodiment, the valve angle θ is set to 26 °, which is further smaller than the conventional lower limit value (45 °).

On the other hand, if the valve angle θ is reduced, the valve body 19 may bite into the valve seat 17, and therefore, in the present embodiment, the PTFE layer is used as the covering layer 62 that covers the surfaces of the valve body 19 and the valve seat 17. Be prepared. As a result, the frictional resistance between the valve body 19 and the valve seat 17 is reduced, and the biting phenomenon is prevented from occurring. Further, by forming the coating layer 62 by PTFE dispersion plating, the durability (corrosion resistance, wear resistance, etc.) of the coating layer 62 can be improved.

Further, in the present invention, the lower limit of the valve angle θ is set to 26 °, and the reason is as follows. Conventionally, if the valve angle θ is sharpened to be smaller than 45 °, the phenomenon of biting into the valve seat 17 may occur, but the calculation of the wedge represented by the following equations 1 and 2 may occur. Using the formula, the slack rate F2 / F1, which is the ratio of the valve opening load (force when pulling out the wedge) F2 and the seating load (force when driving the wedge) F1, is set to the conventional structure (valve body 19 and valve seat). 17 both do not have the coating layer 62 and the valve angle θ is 45 °, which is the lower limit value), and the valve angle θ having a loosening rate similar to this loosening rate is the present application provided with the covering layer 62. The structure (the structure of the present invention) is requested.

F1 = 2 × R × (μ × cos θ + sin θ) ... (Equation 1)

F2 = 2 × R × (μ × cosθ−sinθ)… (Equation 2)

In each of the above equations, R represents the surface pressure [kgf], μ represents the friction coefficient, and θ / 2 (half of the valve angle θ) represents the seating angle [°]. Further, since the friction coefficient when the metals come into contact with each other is about 0.1 to 0.2, the friction coefficient μ of the conventional structure is set to 0.15 by taking the median value of the range, and the friction of the fluororesin. Since the coefficient is about 0.07 to 0.1, the median value of the range is taken and the friction coefficient μ of the structure of the present application is set to 0.085.

Then, when the loosening rate F2 / F1 of the conventional structure (valve angle 45 °) is calculated, F2 / F1 = −0.4683.

On the contrary, for the structure of the present application (valve angle θ), when the valve angle θ at which the loosening rate F2 / F1 = −0.4683 of the conventional structure is obtained, F2 / F1 = −0.4683 and F2 / F1 = −0.4683 are obtained in the following equation 3. , Μ = 0.085 is substituted from the following equation 4, and θ≈26 ° can be obtained.

F2 / F1 = {2 × R × (μ × cos θ − sin θ)} / {2 × R × (μ × cos θ + sin θ)} ... (Equation 3)

-0.4683 = {2 x R x (0.085 x cos θ-sin θ)} / {2 x R x (0.085 x cos θ + sin θ)} ... (Equation 4)

Therefore, according to the structure of the present application, even if the valve angle θ is set to 26 °, a loosening rate similar to the lower limit of the valve angle θ in the conventional structure of 45 ° can be realized. Therefore, the 26 ° is the valve of the present application structure. The lower limit of the angle θ.

In the above-described embodiment, the rotary sliding portion is interposed between the drive unit and the valve body, and when the valve body comes into contact with or separates from the valve seat (contact / separation), the rotational force on the drive unit side is applied to the valve body. An example of applying the present invention to an electric valve having a structure that does not transmit to the valve seat (that is, a structure in which the valve body moves forward and backward without rotating with respect to the valve seat) is given. However, in the present invention, the valve body rotates according to the rotation of the rotor, and the valve body rotates and comes into contact with (contacts / separates with) the valve seat (that is, the valve body rotates with respect to the valve seat). It can also be applied to a structure that moves forward and backward.

In the conventional structure (valve body rotation structure) in which the valve body moves up and down while rotating, for example, a threaded portion (for example, a male screw) formed on the valve shaft of the valve body and a threaded portion (for example, a female screw) fixed to the valve body side are provided. It has a structure in which the rotor is fixed to the valve shaft side, and the valve shaft (valve body) moves up and down as the rotor rotates. In such a valve body rotation structure, the valve body rotates with respect to the valve seat and is brought into contact with each other, so that the friction is large, the friction coefficient at which the metals come into contact is about 0.2, and the valve angle θ is about 60 °. The phenomenon of biting into the valve seat 17 occurs. However, if the present invention is applied to such a structure, the friction coefficient μ is about 0.085, so that the same degree of loosening rate as when the valve angle θ is set to 26 ° in the above embodiment can be realized. Is possible. Therefore, the lower limit of the valve angle θ in the valve body rotation structure is set to 60 °.

In the above-mentioned structure (the structure of the present application, the valve body rotation structure), the surfaces of the valve body 19 and the valve seat 17 are both covered with the coating layer 62, but either the valve body 19 or the valve seat 17 is covered. Even in the configuration of covering with the coating layer 62, the valve angle θ can be set to less than 45 ° (the valve angle θ is less than 60 ° in the valve body rotation structure).

Further, as shown in FIG. 3, the structure of the present application is assumed to include both the base layer 61 and the coating layer 62, but the valve angle θ is set from the conventional lower limit value (45 °, 60 ° in the valve body rotation structure). The effect that can be reduced can be exhibited even in a configuration without the base layer 61, that is, in a configuration in which only the coating layer 62 is formed on the base material (valve body main body portion 63 and valve seat main body portion 64). When only the coating layer 62 was formed on the base metal, the thickness of the coating layer 62 was 5 μm or more, and the effect was observed.

Further, in the structure of the present application, an inverted truncated cone-shaped valve body has been described as an example, but the seating surface (seat portion) of the valve body may be an inverted truncated cone shape, and the shape on the tip side of the seating surface (seat portion). Can be selected in various ways. In this case, the valve angle θ is the angle of the inverted truncated cone of the seating surface, and when the flow rate is low immediately after the valve is opened, the tendency of the flow rate to increase with respect to the increase in the valve opening becomes gentle, and highly accurate control becomes possible.

[Underground layer and its thickness]
The base layer 61 (base layer 61 on the valve body 19 side and base layer 61 on the valve seat 17 side) is a Ni-P plating layer by Ni-P plating (electroless nickel plating). Higher hardness than the base material (a metal valve body body portion 63 such as stainless steel and a metal valve seat body portion 64 such as brass, both of which are materials having a lower hardness than the Ni-P plating layer). This is because the provision of the hard base layer 61 minimizes damage to the valve body 19 and the valve seat 17 due to the biting of foreign matter and prevents an increase in the amount of valve leakage. Further, by providing such a hard base layer 61, it is possible to prevent or suppress the variation in the flow rate due to the scars in which foreign matter is caught and the deterioration of the accuracy of the flow rate control.

The thickness of the base layer 61 is 10 μm or more in this embodiment, and the reason is as follows.

FIG. 5 shows the results of measuring the valve leakage amount after biting a piano wire having a diameter of 15 μm and 130 μm when the thickness of the Ni-P plating layer (base layer) is 5 μm, 10 μm, and 15 μm. It is a thing.

From these test results, the thicker the thickness of the base layer 61, the smaller the valve leakage amount, which is 200 cm ³ / min or less, which is a generally acceptable valve leakage amount for this type of electric valve used in a refrigerant circuit. It can be seen that the thickness of the base layer 61 should be 10 μm or more in order to satisfy the conditions. Therefore, in the present embodiment, the thickness of the base layer 61 is set to 10 μm or more. Considering the cost (treatment time) of plating, the thickness of the base layer 61 is preferably 30 μm or less.

The test shown in FIG. 5 was performed with an electric valve in which only the base layer 61 was formed on the base metal and the covering layer 62 was not formed. When the cross-sectional structure of the scar in which the 130 μm piano wire was bitten was observed after the test of FIG. 5, the thickness of the base layer 61 did not change, and a dent was formed in the base metal portion. The thicker the base layer 61, the smaller the dent.

Further, the condition that the covering layer 62 having various thicknesses was formed on the base layer 61 was added, and the biting test (additional test) of the piano wire (130 μm) of FIG. 5 was performed. As a result, the thickness of the covering layer 62 was increased. A significant decrease in the amount of valve leakage was observed when the thickness was 5 μm or more, and the amount of leakage was further reduced when the coating layer 62 was made thicker.

[Coating layer and its thickness]
First, the thickness of the covering layer 62 for alleviating the biting phenomenon will be described. In order to reduce the valve angle θ at which the biting phenomenon occurs (26 ° in the present application), it is sufficient that the fluororesin is exposed on the surfaces of the valve body 19 and the valve seat 17 even if the base layer 61 is not provided. In the test in which the thickness of the coating layer 62 was 1 μm, the valve angle θ could be set to 26 °. If the thickness of the coating layer 62 exceeds 30 μm, the treatment time is long and the cost is high. Therefore, the coating layer 62 is preferably 30 μm or less. That is, in order to suppress the biting phenomenon, the thickness of the coating layer 62 is 1 μm or more and 30 μm or less.

Next, the thickness of the coating layer 62 for alleviating the adverse effect of foreign matter will be described. When a foreign substance is caught between the valve body 19 and the valve seat 17, the coating layer 62 is temporarily deformed to prevent the plastic deformation of the base material of the valve body 19 and the valve seat 17. Conceivable. Further, it is considered that the influence of the scar can be alleviated by filling the scar generated on the base material of the valve body 19 and the valve seat 17 and the base layer 61 due to the deformation of the covering layer 62 when the valve is closed. In order to exert these effects, the thickness of the coating layer 62 should be 5 μm or more as described above, but if the thickness of the coating layer 62 exceeds 30 μm, the processing time is long and the cost is high. That is, the thickness of the coating layer 62, which alleviates the adverse effects of foreign substances on the base material and the base layer 61 and allows the treatment cost to be tolerated, is 5 μm or more and 30 μm or less.

From the above, when the thickness of the base layer 61 is 10 μm or more and 30 μm or less and the thickness of the coating layer 62 is 5 μm or more and 30 μm or less, both the biting phenomenon and the adverse effects of foreign substances can be alleviated.

Although the embodiments of the present invention have been described above, it is clear to those skilled in the art that the present invention is not limited thereto and various modifications can be made within the scope of the claims. ..

For example, the material constituting the coating layer 62 is PTFE in this embodiment, but other fluororesins such as FEP, PFA, ETFE, modified PTFE and the like may be used. Further, if the valve body 19 and the base layer 61 and the covering layer 62 on the valve seat 17 side are formed at a portion where both (valve body 19 and valve seat 17) come into contact with each other, the object of the present invention can be achieved. Therefore, it is not always necessary to provide the base layer 61 and the coating layer 62 on the entire outer surface of the valve body 19 or the entire inner surface of the valve body 11.

Further, the electric valve according to the present invention can typically be preferably used for a refrigerating cycle device equipped with a refrigerant circuit such as an air conditioner (air conditioner), a freezer / refrigerator, but the present invention is not limited to these. It is possible to use the electric valve according to the present invention for various purposes. Therefore, the "fluid" referred to in the present invention includes various liquids and gases (gas) in addition to heat media (refrigerant and heat medium).

1 Electric valve 11 Valve body 12 Valve chamber 13 First flow path port 14, 16 Pipe fitting 15 Second flow path port 17 Valve seat 18 Valve port 19 Valve body 19a Needle part (seating part)
19b Fitting hole 20 Spring case 21 Compression coil spring 22 Ball-shaped joint 23 Ball 24 Ball receiving seat 25 Base plate 26 Bearing member 26a Fitting insertion hole 27 Female threaded part 28 Threaded drive member 28a Plate-shaped part 29 Male threaded part 30 Thread feed mechanism 31 Output Shaft 31a Fitting groove 32 Shaft 33 Support member 34 Can 35 Cylindrical member 41 Stepping motor 42 Stator 43 York 44 Bobbin 45 Coil 46 Resin mold cover 47 Rotor 48 Sun gear member 48a Sun gear 49 Planetary gear 50 Shaft 51 Carrier 52 Internal gear 53 Output gear 54 Mysterious planetary gear reduction mechanism 55 Ring gear 61 Underlayer layer 62 Coating layer 63 Main body of valve body (base material)
64 Main body of valve seat (base material)

Claims (7)

A valve body provided with a valve chamber and a valve opening with a valve seat,
A valve body that controls the amount of fluid passing by moving back and forth without rotating with respect to the valve seat,
A first flow path port communicating with the valve chamber via the valve port,
The second flow path port communicating with the valve chamber and
It is provided with an electric drive unit that drives the valve body.
The valve body
The valve includes a seating portion having an inverted conical shape or an inverted truncated cone shape whose diameter gradually decreases toward the valve seat, and is inserted into the valve opening when the seating portion is seated on the valve seat and the valve is closed. An electric valve with a needle that can close the mouth.
The angle formed by the opposing bus wires of the seating portion is set to 26 ° or more and less than 45 °, and the angle is set to 26 ° or more and less than 45 °.
An electric valve characterized in that a coating layer containing a fluororesin is provided on the surface of either one or both of the seat and the valve seat. A valve body provided with a valve chamber and a valve opening with a valve seat,
A valve body that controls the amount of fluid passing by moving forward and backward while rotating with respect to the valve seat,
A first flow path port communicating with the valve chamber via the valve port,
The second flow path port communicating with the valve chamber and
It is provided with an electric drive unit that drives the valve body.
The valve body
The valve includes a seating portion having an inverted conical shape or an inverted truncated cone shape whose diameter gradually decreases toward the valve seat, and is inserted into the valve opening when the seating portion is seated on the valve seat and the valve is closed. An electric valve with a needle that can close the mouth.
The angle formed by the opposing bus wires of the seating portion is set to 26 ° or more and less than 60 °, and the angle is set to 26 ° or more and less than 60 °.
An electric valve characterized in that a coating layer containing a fluororesin is provided on the surface of either one or both of the seat and the valve seat. The electric valve according to claim 1 or 2, wherein the fluororesin is any one of PTFE, FEP, PFA, ETFE, and modified PTFE. The electric valve according to any one of claims 1 to 3, wherein a base layer having a hardness higher than that of the base material is provided between the coating layer and the base material. The motorized valve according to claim 4, wherein the base layer is a Ni-P plated layer. The motorized valve according to claim 5, wherein the base layer has a thickness of 10 μm or more and 30 μm or less. The motorized valve according to any one of claims 4 to 6, wherein the coating layer has a thickness of 5 μm or more and 30 μm or less.

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