JP3604756B2 - Electric valve - Google Patents

Description

[0001]
[Industrial applications]
The present invention relates to a motor-operated valve used for controlling a flow rate of a fluid such as a refrigerant used in a refrigeration cycle.
[0002]
[Prior art]
The motor-operated valve used in the refrigeration cycle has a configuration in which, for example, a rotary motion of a stepping motor is converted into a linear motion of a valve by a screw mechanism, and a flow passage area between the valve and the orifice of the valve body is controlled.
Specifically, a guide bush having a female screw portion is attached to the valve body, a male screw portion is provided on a valve body that is integral with the rotor of the stepping motor or a valve holder that supports the valve body, and the two screw portions are screwed together.
The refrigerant flowing into the valve body flows into the can housing the rotor and is circulated. This refrigerant also infiltrates the screw portion and lubricates the screw portion.
In a refrigerant such as Freon, a lubricating oil component is contained to lubricate the screw portion.
[0003]
[Problems to be solved by the invention]
However, in consideration of the influence on the natural environment, alternative refrigerants are being used. Depending on the type of this alternative refrigerant, it may be difficult to contain a lubricating oil component. Since the refrigerant has a high cleaning function and has an action of washing out lubricating oil and the like adhering to the screw portion, such an alternative refrigerant may cause poor lubrication of the screw portion.
The present invention provides a motor-operated valve that solves this kind of problem.
[0004]
[Means for Solving the Problems]
An electric valve according to the present invention includes a valve body having a valve chamber and an orifice, a cylindrical can attached to the valve body, a stator member arranged outside the can, and a rotor member arranged inside the can. And a valve holder integrated with the rotor member, a valve body attached to the valve holder, and a bush fixed to the valve body . A motor-operated valve which is operated in a state exposed to a low coolant, wherein a plated coating layer having lubricity is formed on the screw portion. And this plating coating layer is made of a material containing polytetrafluoroethylene in nickel.
[0005]
[Action]
Since the plating coating layer has lubricating properties, lubrication of the screw portion is ensured even without adding a lubricant, and no inconvenience due to poor screwing occurs.
[0006]
【Example】
FIG. 1 is an explanatory diagram showing the overall configuration of a motor-operated valve according to an embodiment of the present invention, and FIG. 2 is an explanatory diagram showing the main part thereof.
The motor-operated valve denoted by reference numeral 1 as a whole has a cylindrical can 10 and a motor mold 20 fitted on the outer periphery of the can 10. The motor mold 20 is formed by molding a resin, and includes a stator yoke 21, a bobbin 24, and a magnet wire 22 wound around the bobbin 24 inside. This magnet wire 22 is connected via a lead wire 23 to a connector 34 inside a housing 30 attached to the motor mold 20. The connector 34 is connected to a control device via a lead wire 36. The bobbin 30 is filled with an epoxy resin 32.
[0007]
The motor mold 20 is detachably fitted to the outer periphery of the can 10 in the axial direction, and is fixed to the motor mold 20 by a stopper 28 attached with a screw 26. On the outer peripheral portion of the can 10, an annular groove 11 for receiving the stopper 28 is formed.
The lid member 12 is attached to the opening of the can 10 by means such as welding, and the valve body 40 is attached to the opening of the lid member 12. The valve body 40 is made of, for example, a copper alloy, and has a valve chamber 42, an inlet 43, and an outlet 44. Outlet 44 forms an orifice that controls the flow of the valve.
[0008]
An inlet pipe 50 communicates with the inlet 43 of the valve body 40, and an outlet pipe 52 communicates with the orifice outlet 44.
A guide bush 90 is inserted into the inner diameter of the valve body 40. The guide bush 90 has an internal thread portion 92 on the inner diameter portion, and a valve holder 70 having an external thread portion 74 screwed to the internal thread portion 92 is attached. The valve holder 70 has a cylindrical shape, and a valve body 80 is slidably inserted into a lower portion thereof. The valve body 80 is constantly urged outward by a coil spring 72 inserted into a hollow portion of the valve holder 70, and the protrusion of the valve body is regulated by a collar 82 which is press-fitted into an inlet portion of the valve holder. Is done.
[0009]
A shaft 64 is provided above the valve holder 70. A plastic sleeve 60 is integrally formed on the outer periphery of the shaft 64 and the valve holder 70, and a bond magnet 62 is formed on the outer periphery of the plastic sleeve 60. The bond magnet 62 functions as a motor rotor.
The upper end of the shaft 64 is supported by a bearing member 14 disposed on the back surface of the top of the can 10. The coil spring 66 provided on the shaft 64 is used to press the valve holder 70 toward the guide sleeve 90 when the rotor rotates and rises together with the valve holder 70 to remove the screwing of the screw portion. Things.
The stopper member 77 attached to the upper part of the guide bush 90 regulates the lower end position of the rotor, is formed of a resin material, and comes into contact with the stopper portion 78 of the sleeve 60.
[0010]
The valve chamber 42 of the valve body 40 communicates with the inside of the can 10 through the passage 46, and the inside of the can 10 communicates with the hollow portion of the valve holder through the hole 73. Therefore, the refrigerant flowing into the valve chamber 42 is charged into the interior of the can 10, and the refrigerant flows into the screw portion between the female screw portion 92 of the guide bush 90 and the male screw portion 74 of the valve holder 70.
The refrigerant has a strong cleaning action, and therefore, the lubricating component of the screw portion is also easily removed. Therefore, the threaded portion is apt to cause poor lubrication, and is liable to wear and seize.
[0011]
As a result, the accuracy of the screw engaging portion is deteriorated, the function is reduced, and the operation is defective.
As a means to ensure lubrication of this thread, the female thread may be made of a sintered alloy.However, a mold for molding the sintered alloy is required, and the sintered alloy is damaged by impact. And the strength of the threaded portion is insufficient.
Further, a technique of baking a lubricant of molybdenum disulfide on a screw portion has been proposed. However, this lubricant peels off from the base material due to repeated sliding of the threaded portion, and falls, resulting in a problem in durability.
[0012]
The present invention forms a motor-operated valve with high lubricity and durability by forming a plating coating layer on the surface of the driving screw portion.
That is, the female screw portion 92 formed on the inner peripheral surface of the guide bush 90 has, for example, a screw thread having a pitch of about 0.6 mm. Therefore, the female screw portion 92 is plated with (NI + PTFE) containing polytetrafluoroethylene in nickel to form a plating layer on the surface of the screw portion.
Of course, the plating layer may be applied to the male screw part, and since the male screw part is on the driving side, it is more preferable as the screw part to which the plating layer is applied. It is needless to say that the plating layer can be applied to both the male screw portion and the female screw portion.
[0013]
The plating means is the same as that of general electroless nickel plating.
This plated coating of NI + PTFE has high hardness, excellent slipperiness, and high abrasion resistance. Therefore, by forming this plating coating layer on one of the drive screws, even in the case of an electric valve that controls a refrigerant body having high cleanability and low lubricity, the drive screw portion of the valve body always operates normally. It can function and exhibit predetermined performance. Note that the plating coating layer may be formed on the male screw portion 74 of the mating valve holder 70 instead of the female screw portion 92 of the guide bush 90. Further, a plating coating layer may be formed on both the male screw part 74 and the female screw part 92.
[0014]
【The invention's effect】
As described above, the present invention relates to a motor-operated valve of an air conditioner which needs to operate while being exposed to a refrigerant having a strong detergency and a low lubricating property. A plating coating layer is formed on a drive screw portion for converting into motion. The plating coating layer is formed of a material containing polytetrafluoroethylene in nickel and has high abrasion resistance and high lubricity.
Therefore, the present invention is effective for a motor-operated valve of an air conditioner that handles a refrigerant with low lubricity or the like like a substitute refrigerant.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram showing a configuration of a motor-operated valve to which the present invention is applied.
FIG. 2 is an enlarged view of a main part of FIG.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 electric valve 10 can 12 lid member 14 bearing member 20 motor mold 21 stator yoke 24 bobbin 30 housing 40 valve body 42 valve chamber 44 orifice 60 plastic sleeve 62 bond magnet 70 valve holder 74 male screw part 80 valve body 90 bush 92 female screw part

Claims (1)

A valve body having a valve chamber and an orifice, a cylindrical can attached to the valve body, a stator member disposed outside the can, a rotor member disposed inside the can, and an integral part of the rotor member. A valve holder, a valve body attached to the valve holder, and a bush fixed to the valve body, the valve holder and the bush are provided with a threaded portion screwed together , and a passage communicating the valve chamber and the inside of the can. In the case of an electric valve in which a refrigerant having a strong detergency and a low lubricity flows from the valve chamber into the inside of the can and the screw portion, the surface of the male screw portion formed on the valve holder and the female screw formed on the bush is made of polytetrafluoroethylene on nickel. A motor-operated valve having a plating coating layer made of a material containing:

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