JPH10205638A - Electrically driven flow rate control valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of separation of a joining part of parts while preventing stress erosion on a part exposed to a substitute coolant by carrying out Ni-plating treatment on at least an inner side surface of a can body for housing a rotor inside. SOLUTION: When a stator coil 32 of a motor 30 is excited by an electric signal from an outside, a rotor 33 is rotated by a predetermined range on the basis of an electric signal rate. Since the rotor 33 is screwed around a fixed guide 40 at its screw parts 34a, 40a, the rotor 33 is moved in a vertical predetermined direction by its rotation, a valve stem 20 is vertically moved in the same as that of the rotor 33, a valve element 17 is moved from a valve seat body 21 by moving an interval, and the flow rate of a coolant to be controlled is controlled according to a rate of an electric signal applied on the stator coil 32. In a control valve 10, Ni-plating treatment is carried out on at least an inner side surface of a can body 31c which is draw mold-worked. It is thus possible to prevent the crack of stress erosion which is caused when the can body 31c is used.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric flow control valve, and more particularly to an electric flow control valve for controlling a flow rate of a fluid such as a refrigerant used in a refrigeration cycle such as cooling and heating.

[0002]

2. Description of the Related Art A conventional electric flow control valve used in a refrigeration cycle includes a valve body having a valve seat and a valve body in a valve chamber, and a stepping motor and the like disposed on the valve body. An electric motor, wherein the electric motor is a cylindrical closed case press-formed from a non-magnetic stainless steel material, a stator coil disposed outside the closed case, and disposed in a case inner chamber of the closed case. And a rotor. The rotor is formed of an aluminum sleeve disposed on the inner peripheral side and a ferrite magnet disposed on the outer peripheral side.

Further, a long rod-shaped valve shaft extends from the case inner chamber to the valve chamber, and one end of the valve shaft is fixed to the aluminum sleeve of the rotor, and the other end is connected to the other end. The valve is fixed. In the aluminum sleeve of the rotor, a female screw is engraved on an inner periphery, and a lower end thereof is fixed to an upper portion of the valve body, and a stainless steel fixing guide is engraved with an external thread on an outer periphery, The female screw is rotatably supported by being screwed into the male screw.

[0004] The electric flow control valve having the above-described structure acts to rotate the rotor by energizing and exciting the stator coil. Since the inner circumference of the rotor is screwed to the outer circumference of the fixed guide,
Vertical movement is performed by the rotation. Since the valve shaft is fixed to the rotor, the valve shaft also moves up and down by the up and down movement of the rotor, and the valve body fixed to the lower end of the valve shaft moves its flow passage gap with respect to the valve seat. Is adjusted, the flow rate of the refrigerant passing through the electric flow control valve is adjusted.

[0005] The case inner chamber and the valve chamber are in communication with each other, and the refrigerant in the valve chamber flows into the case inner chamber. Is supplied to the threaded portion of the female screw and the male screw of the aluminum sleeve and the fixed guide, thereby lubricating the threaded portion and improving the rotation of the threaded portion. ing.

However, in the electric flow control valve as described above, a galling phenomenon occurs in which the screwed portion is fixed to the screwed portion between the sleeve of the rotor and the fixed guide, so that the stator coil is energized to be excited. Accordingly, even if the rotor is driven to rotate, there is a problem that the rotor does not rotate well, and metal chips or abrasion powder may be mixed in the middle of the piping of the refrigeration cycle.

The metal abrasion powder in the piping of the refrigeration cycle, etc., is formed on the female screw portion of the sleeve based on a galling phenomenon at the screwing portion between the sleeve of the rotor of the electric flow control valve and the fixed guide. Is abrasion powder scraped off by the male screw portion of the fixed guide, and the abrasion powder is delivered along with the refrigerant to the middle of the refrigeration cycle piping via the valve chamber.

Further, the galling phenomenon at the threaded portion between the sleeve of the rotor and the fixed guide is due to insufficient supply of oil for lubrication to the threaded portion.

Further, in the rotor, an inner sleeve and an outer ferrite magnet are adhered and fixed with an adhesive.
There is a possibility that a problem that the adhesive strength is reduced may occur.

In order to provide an electric flow control valve which does not cause a galling phenomenon and does not generate abrasion powder at the threaded portion between the sleeve of the rotor and the fixed guide, the applicant of the present invention has proposed Proposed a configuration in which the sleeve is made of stainless steel, a magnet is arranged on the outer peripheral side of the sleeve, and the magnet and the stainless steel sleeve are bonded with an acrylic adhesive and fixed with a toothed retaining ring. (Japanese Patent Application No. 8-243472).

Since the rotor of the electric flow control valve is made of stainless steel, it can be used for a long period of time by increasing the durability without causing a galling phenomenon at the threaded portion between the sleeve and the fixed guide. It is.

[0012]

Recently, for example, a lithium bromide solution has been used in an absorption refrigeration cycle. However, since the lithium bromide solution is highly corrosive, the material is made of stainless steel. However, there is a problem that the contact portion is corroded even if the contact portion is made.

That is, the cylindrical closed case made of a non-magnetic stainless material is formed by drawing with a press, and is subjected to stress distortion. Therefore, in the long-term use, an alternative refrigerant such as the lithium bromide is used. However, there is a problem that stress corrosion cracking occurs in the inner portion where the metal contacts.

In addition, crevice corrosion occurs at the joint between the stainless steel sleeve and the ferrite magnet on the outer peripheral side, and the joint is bonded with an acrylic adhesive (Loctite 272 or the like). However, there is a problem that the acrylic adhesive may be hydrolyzed during use and the joint may come off.

The present invention has been made in view of such a problem, and an object of the present invention is to prevent stress corrosion and the like of a portion exposed to an alternative refrigerant such as lithium bromide. Another object of the present invention is to provide a motor-operated flow control valve that eliminates peeling of a joint between components.

[0016]

In order to achieve the above object,
The electric flow control valve of the present invention includes a valve body having a valve body in a valve chamber, and an electric motor mounted and fixed on an upper part of the valve body,
The electric motor has a closed case, a stator coil disposed outside the closed case, and a rotor disposed in an inner case inner chamber, and the valve body is connected to the rotor by a valve shaft. In addition, the valve chamber and the case inner chamber allow communication of control fluid, and the closed case includes a can body, and at least an inner surface of the can body is subjected to Ni plating. It is characterized by having.

In another aspect of the electric flow control valve of the present invention, the rotor has a sleeve disposed inside and a magnet disposed outside, and the space between the sleeve and the magnet is filled and bonded with epoxy resin. Features. Furthermore,
As another preferred embodiment, the sleeve and the fixed guide attached and fixed to the valve body are screwed together, and a screw plating portion of the sleeve and the fixed guide is subjected to a composite plating process based on Ni plating. It is characterized by:

The motor-operated flow control valve of the present invention having the above-described structure is arranged such that when the stator coil of the electric motor is excited by an external electric (pulse) signal, the rotor is rotated by a predetermined amount based on the electric signal amount. Rotate. Since the rotor is screwed to the fixed guide with its screwing thread,
The rotor moves in a predetermined vertical direction by the rotation thereof, and also moves the fixed valve shaft in a predetermined vertical direction, thereby controlling the flow rate of the refrigerant to the electric signal applied to the stator coil. Control according to the amount of

At least the inner surface of the can body is made of N
By performing the i-plating treatment, corrosion of the inner surface is prevented, and stress corrosion cracking during use is prevented even if the can body is drawn and formed by a press or the like.

In addition, since the sleeve of the rotor is made of stainless steel and an epoxy resin is selected as an adhesive at a joint with the ferrite magnet and filled with the epoxy resin, the epoxy resin may be hydrolyzed during use. In addition, even when used for a long time, the peeling phenomenon does not occur between the sleeve and the magnet.

Further, since a composite plating process based on Ni plating is applied to the screw portion of the screw between the fixed guide and the sleeve, the screw surface of the male screw and the female screw is formed based on the load of the refrigerant fluid. Even when stress is generated, stress corrosion does not occur on the screw surface, and the slidability of the threaded portion does not deteriorate.

[0022]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an electric valve 10 according to the present embodiment.
A valve body 11 formed of a stainless steel metal material has a motor 31 such as a stepping motor mounted and fixed on an upper portion thereof, and a pipe connection portion 12 threaded outside the valve body 11. , 13 and an opening 18 into which a plug 19 is screwed. The upper part of the plug 19 of the valve main body 11 is configured as a valve chamber 15, in which the valve element 17 and the valve seat 21 are arranged on the same axis. The valve body 17 is attached and fixed to a valve shaft 20, and the valve seat body 21 is screwed to the valve body 11 so that the vertical position can be adjusted.

In the pipe connection section 12, an inlet-side passage 1 is provided.
2a is drilled, and an outlet side passage 13a is drilled in the pipe connection portion 13 so that both passages 12a, 13a are formed.
a is connected to the valve chamber 15 and has strainers 12b and 13b in both passages.

The valve shaft 20 has an intermediate portion slidably supported by an upper portion 11a of the valve body 11, and the upper portion 20a of the valve shaft 20 is inserted into the electric motor 31. ing.

The electric motor 30 has a cylindrical sealed case 31 formed of a non-magnetic stainless steel plate mounted and fixed on the upper portion 11a of the valve body 11, and is disposed outside the sealed case 31. And the rotor 33 disposed in the case inner chamber 31a of the closed case 31. The rotor 33 is formed by a stainless steel sleeve 34 disposed on the inner peripheral side and a ferrite magnet 39 disposed on the outer peripheral side.
An electric signal is applied to the stator coil 32 from the outside of the electric motor 30 via a wiring 32a.

The sleeve 34 of the rotor 33
As shown in FIG. 2, the fitting joint and the magnet 39 are bonded and fixed with an epoxy resin adhesive A, and the upper part thereof is fixed by pushing a toothed retaining ring 44. . The toothed retaining ring 44 is formed of an elastic material such as a spring material, and a plurality of inner teeth elastically contact the outer periphery of the sleeve 43.

[0027] The sealed casing 31 is formed in the lower cover 31b and the can body 31c, the scanning body 31c, as shown in FIG. 3, a bottomed cylinder having a flange portion 31c ₁ with the barrel 31c ₃ to be molded squeezed with a press or the like, and a full open stopper 38 to the bottom 31c ₂ sealed fitting engagement. The can body 31
The entire periphery of c is plated with Ni to a thickness of about 5 to 10 μm. The can body 31c and the full-open stopper 38 may be fitted and locked after plating the entire periphery thereof, or may be plated after being fitted and locked. Further, since the can body 31c is contacted with the refrigerant on the inner surface, the can body 31c may be plated only inside.

[0028] The lower cover 31b is for engagement with the flange portion 31c ₁ of the can body 31c, full-close stopper 3
5, the sleeve 3 of the rotor 33
A valve closing restricting pin 36 screwed at the lower end of the valve 4 so as to adjust the amount of protrusion comes into contact with the outer peripheral surface of the fully closed stopper 35, and regulates the valve closing limit of the rotor 33. A valve opening regulating pin 37 is screwed to the upper end of the sleeve 34 so as to adjust the amount of protrusion.
When the valve 7 is fully opened, it comes into contact with the fully open stopper 38 at the upper end of the can body 31c to regulate the valve opening limit of the rotor 33.

An upper portion 11a of the valve body 11 is provided with a stainless steel hollow cylindrical fixed guide 4 which is coaxial with the valve shaft 20 and slidably inserts the valve shaft 20 therein.
0 is fixed. A male screw 40a is engraved on the outer periphery of the fixed guide 40, and a female screw 34a is engraved on the inner periphery of the center of the sleeve 34. The male screw 40a and the female screw 34a It is screwed. As shown in FIG. 2, each of the threaded portions of the male screw 40 a and the female screw 34 a is formed of a composite plating C based on Ni plating (for example, after performing Ni plating, and then using Teflon resin). A two-layer process of applying a powder layer).

The valve shaft 2 extends upward from the valve body 11, penetrates through the cylinder of the fixed guide 40, and further extends upward.
The upper end 20a of the C-ring 4 extends through a hole formed in the center of the connection wall at the upper part of the sleeve 34, and its protruding end is
1 and between the intermediate step of the valve shaft 20 and the inner washer 42 of the connecting wall of the sleeve,
Is interposed in a buffer spring 43 for urging the valve in the valve closing direction.

When the stator coil 32 of the electric motor 30 is excited by an external electric (pulse) signal, the rotor 33 is driven by the electric signal. It rotates a predetermined amount based on the amount. Since the rotor 33 is screwed to the fixed guide 40 at the screw portions 34a and 40a, the rotor 33 moves in a predetermined vertical direction by its rotation,
Similarly, the fixed valve shaft 20 is moved in a predetermined vertical direction, and the valve body 17 is moved by a gap between the valve body 17 and the valve seat body 21, and is controlled by the electric flow control valve 10. The flow rate of the refrigerant is controlled in accordance with the amount of the electric signal applied to the stator coil 32.

The motorized flow control valve 10 of the present embodiment is characterized in that at least the inner surface of the can body 31c drawn and formed by a press or the like is subjected to Ni plating. Fully open stopper 3
8 was subjected to electroless Ni plating and then immersed in a lithium bromide solution for a service life of, for example, 10 to 15 years.
No cracks occurred. That is, by performing Ni plating on at least the inner surface of the can body 31c, corrosion of the inner surface is prevented, and even if the can body 31c is drawn by a press or the like, it is not used. Stress corrosion cracking is prevented.

Further, the electric flow control valve 10 of the present embodiment
Is characterized in that the sleeve 34 of the rotor 33 is made of stainless steel, and a joint between the sleeve 33 and the ferrite magnet 39 is filled with an epoxy resin as an adhesive, and the sleeve 34 and the magnet 39 are bonded with an epoxy resin. After that, a heat cycle test in which the temperature was repeated in a temperature range of 120 ° C. to 20 ° C. by immersion in lithium bromide was performed at a cycle number corresponding to the above-mentioned service life, but the sleeve 34 and the magnet 39 were separated. Did not. Further, after the sleeve 34 and the magnet 39 are bonded with an epoxy resin, the sleeve 34 and the magnet 39 are immersed in a gas phase or a liquid phase of lithium bromide.
The immersion test was performed at 00 ° C for 2000 hours.
No peeling of the magnet 4 from the magnet 39 occurred. That is, since the epoxy resin as the adhesive is not hydrolyzed during use, there is no change in the bonding strength between the rotor 33 and the ferrite magnet 39. No peeling phenomenon occurs between the film 39 and the substrate.

Further, since the threaded portion between the male screw 40a and the female screw 34a of the fixed guide 40 and the sleeve 34 is subjected to a composite plating process based on Ni plating, it is possible to control the load based on the load of the refrigerant fluid. Therefore, even if stress is generated on the screw surfaces of the male screw 40a and the female screw 34a, the slidability of the screw portion does not deteriorate.

In the electric flow control valve 10 of the above embodiment, the lower lid 31b of the closed case 30 is formed separately from the valve body 11, but the electric flow control valve 1 shown in FIG.
It can also be molded integrally with the valve body 11 like 0 ′. In this case, the fully closed stopper 35 ′ is also connected to the valve body 1.
1 and can be molded and placed in advance.

Further, the electric flow control valve 10 of the above embodiment
Has shown that the surface of the can body 31c of the closed case 30 is Ni-plated, but the present invention is not limited to this, and a surface treatment such as painting may be performed.

Further, if necessary, a material such as a spring and a tome contacted by a coolant such as lithium bromide may be made of stainless steel, and its surface may be subjected to Ni plating to cope with stress corrosion cracking.

[0038]

As will be understood from the above description, the motor-operated flow control valve of the present invention has a stainless steel can body plated with Ni and a threaded portion between the fixed guide and the sleeve formed with N.
Since a composite plating process based on i-plating has been applied,
For example, even if a substitute refrigerant (such as lithium bromide) is used instead of Freon as a refrigerant, stress corrosion cracking does not occur in the can body, and sliding deterioration of the screw portion is prevented.

Also, since the epoxy resin is used for joining the ferrite magnet and the sleeve, the resin is not hydrolyzed, and the phenomenon of peeling between the sleeve and the magnet does not occur.

[Brief description of the drawings]

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

FIG. 2 is a longitudinal sectional view of a rotor and a fixed guide of the electric flow control valve of FIG. 1;

FIG. 3 is a longitudinal sectional view of a can body of a closed case of the electric flow control valve of FIG. 1;

FIG. 4 is a longitudinal sectional view of an electric flow control valve according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Electric flow control valve 11 ... Valve main body 15 ... Valve chamber 17 ... Valve body 20 ... Valve shaft 21 ... Valve seat body 30 ... Electric motor 31 ... Sealed case 32 ... Stator coil 33 ... Rotor 34 ... Sleeve 34a ... Female screw Part 39: Magnet 40: Fixed guide 40a: Male screw part 44: Toothed retaining ring

Claims (4)

[Claims] 1. A valve body having a valve body in a valve chamber, and a motor mounted and fixed on an upper portion of the valve body, wherein the motor is a sealed case, a stator coil disposed outside the sealed case, and A rotor disposed in an inner case inner chamber, and the valve body is connected to the rotor by a valve shaft, and the valve chamber and the case inner chamber can communicate control fluid. In the electric flow control valve described above, the closed case includes a can body, and at least an inner surface of the can body is subjected to a Ni plating process. 2. The closed case of the electric motor includes a lower lid fitted to the can body, and the lower lid is formed integrally with or separately from the valve body.
3. The electric flow control valve according to claim 1. 3. A valve body having a valve body in a valve chamber, and a motor mounted and fixed on an upper portion of the valve body, wherein the motor is a sealed case, a stator coil disposed outside the sealed case, and A rotor disposed in an inner case inner chamber, and the valve body is connected to the rotor by a valve shaft, and the valve chamber and the case inner chamber can communicate control fluid. An electric flow control valve according to claim 1, wherein the rotor has a sleeve disposed inside and a magnet disposed outside, and a gap between the sleeve and the magnet is filled and adhered with epoxy resin. 4. A valve body having a valve body in a valve chamber, and a motor mounted and fixed on an upper portion of the valve body, wherein the motor is a sealed case, a stator coil disposed outside the sealed case, and A rotor disposed in an inner case inner chamber, and the valve body is connected to the rotor by a valve shaft, and the valve chamber and the case inner chamber can communicate control fluid. In the motorized flow control valve described above, the rotor has a sleeve disposed inside, and the sleeve and a fixed guide attached and fixed to the valve body are screwed together, and a screwing portion of the sleeve and the fixed guide is screwed. N
An electric flow control valve characterized by performing a composite plating process based on i-plating.