JP7141423B2 - Electric valve and refrigeration cycle system - Google Patents

Description

The present invention relates to a motor-operated valve and a refrigeration cycle system using the motor-operated valve.

2. Description of the Related Art Electric valves used in package air conditioners, room air conditioners, refrigerators, etc. are conventionally known (see Patent Document 1, for example). In the electric valve 100, as shown in FIG. 6, when the stepping motor is driven to rotate the rotor 103, the valve body 114 moves in the direction of the central axis L due to the feeding action of the female thread 131a and the male thread 121a. . As a result, the opening and closing of the valve port 121 is adjusted, and the flow rate of the refrigerant flowing in from the pipe joint 111 and flowing out from the pipe joint 112 is controlled.

JP 2012-172839 A

By the way, in the motor-operated valve 100 described above, there is a possibility that good operability of the motor-operated valve 100 cannot be obtained due to the gap between the male screw 121a and the female screw 131a.

For example, when the valve shaft 141 is welded to the through-hole 133a of the bushing member 133, the valve shaft 141 may deviate from the axis and be fixed in a biased position as shown in FIG. In this case, if the meshing gap between the male thread 121a and the female thread 131a is large, the rotor 103 rotates around a biased axis, impairing the operability of the motor-operated valve 100 and making it difficult to rotate the rotor 103 with high accuracy. Become.

SUMMARY OF THE INVENTION An object of the present invention is to provide a motor-operated valve capable of properly rotating a rotor and having high operability, and a refrigeration cycle system using the motor-operated valve.

The motor operated valve of the present invention is
Rotational motion of the rotor accommodated in the inner circumference of the case is converted into linear motion by threading the male thread of the male thread member and the female thread of the female thread member, and is accommodated in the valve body based on this linear motion. A motor-operated valve that axially moves a valve element with a
The female screw member is made of resin,
The rotor is made of resin containing magnetic powder,
a cylindrical bushing member formed with a through hole through which the male threaded member is fixed and transmitting the rotation of the rotor to the male threaded member;
The male screw member is threadedly engaged with the female screw member in a state where one end on the rotor side is free with respect to the through hole of the bush member,
A welding region is formed between the end surface of the end portion where the outer circumference of the bushing member is reduced in diameter and the side surface of the male screw member protruding from the bushing member,
A gap is formed between the bushing member and the male threaded member, and the bushing member is fixed to the male threaded member by welding,
The difference between the inner diameter of the through hole and the outer diameter of the male screw member is
a difference between the thread diameter of the male thread of the male thread member and the root diameter of the female thread of the female thread member ;
The difference is smaller than the smaller one of the difference between the root diameter of the male screw of the male screw member and the crest diameter of the female screw of the female screw member.

By narrowing the gap between the through hole of the bushing member and the male screw member in this way, it is possible to suppress the eccentricity of the rotor with respect to the axial center during rotation of the rotor. Therefore, the rotor can be properly rotated, and an electrically operated valve having high operability can be provided.

Further, the motor operated valve of the present invention is
The difference between the inner diameter of the case and the outer diameter of the rotor is
The difference between the ridge diameter of the male thread of the male thread member and the root diameter of the female thread of the female thread member, and the difference between the root diameter of the male thread of the male thread member and the ridge diameter of the female thread of the female thread member. is larger than whichever is larger.

By widening the gap between the case and the rotor in this way, it is possible to prevent the rotor from coming into contact with the inside of the case when the rotor rotates and sliding against the inner peripheral surface of the case.

Further, the motor operated valve of the present invention is
The female screw member is made of resin.
Thereby, the coefficient of friction of the female screw member can be reduced, and the durability can be improved.

Further, the refrigeration cycle system according to the present invention is
A refrigeration cycle system including a compressor, a condenser , an expansion valve, and an evaporator, characterized in that the above-described motor-operated valve is used as the expansion valve.

ADVANTAGE OF THE INVENTION According to the invention which concerns on this invention, a rotor can be rotated appropriately and the motor-operated valve which has high operability, and a refrigerating-cycle system using this motor-operated valve can be provided.

1 is a cross-sectional view of an electrically operated valve according to an embodiment; FIG. 4 is an enlarged cross-sectional view of a screw-coupled portion of the motor-operated valve according to the embodiment; FIG. 4 is an enlarged cross-sectional view of a gap between valve shafts of bush members according to the embodiment; FIG. 4 is an enlarged cross-sectional view of a gap between a case and a rotor according to the embodiment; FIG. FIG. 5 is a diagram showing a state in which the axis of the rotating shaft of the motor-operated valve is tilted; FIG. 10 is a cross-sectional view of a conventional electric valve; FIG. 4 is a cross-sectional view illustrating a state in which the valve shaft of the motor-operated valve is deviated from the axis and fixed to the bush member.

A motor-operated valve according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an electrically operated valve 2 according to an embodiment. In this specification, the terms "upper" and "lower" are defined in the state shown in FIG. That is, the rotor 4 is positioned above the valve body 17 .
In the electric valve 2, the valve main body 30 is integrally connected by welding or the like to the lower opening side of a cylindrical cup-shaped case 60 made of non-magnetic metal.

Here, the valve body 30 is made of metal such as stainless steel and has a valve chamber 11 therein. A first pipe joint 12 made of stainless steel or copper, which directly communicates with the valve chamber 11 , is fixedly attached to the valve body 30 . Furthermore, a valve seat member 16 having a valve port 16a with a circular cross section is incorporated in the lower inner side of the valve body 30 . A second pipe joint 15 made of stainless steel or copper, which communicates with the valve chamber 11 via a valve port 16a, is fixedly attached to the valve seat member 16. As shown in FIG.

A rotatable rotor 4 is accommodated in the inner circumference of the case 60 , and a valve shaft 41 is arranged at the axial center portion of the rotor 4 via a bush member 33 . The valve shaft 41 and the rotor 4 coupled by the bushing member 33 move integrally in the vertical direction while rotating. A male screw 41a is formed on the outer peripheral surface of the valve shaft 41 near the intermediate portion. In this embodiment, the valve shaft 41 functions as a male screw member.

Here, the bushing member 33 is a cylindrical member made of metal such as stainless steel and having a through hole 33a formed in the center through which the valve shaft 41 passes. The rotor 4 is made of a magnetic material such as a resin material such as polyphenylene sulfide (PPS) containing magnetic powder or a magnetic material such as a ferrite magnet. Further, the bush member 33 is fixed to the rotor 4 by insert molding. The valve shaft 41 is fixed to the bush member 33 by passing the valve shaft 41 through the through hole 33a of the bush member 33 and welding 41c. Rotation of the rotor 4 is transmitted to the valve shaft 41 by fixing the rotor 4 and the bush member 33 and the bush member 33 and the valve shaft 41 in this manner.

A stator composed of a yoke, a bobbin, a coil, and the like (not shown) is arranged around the outer periphery of the case 60, and the rotor 4 and the stator constitute a stepping motor.
A guide support 52 is fixed to the ceiling surface of the case 60 . The guide support member 52 has a cylindrical portion 53 and an umbrella-shaped portion 54 formed on the upper end side of the cylindrical portion 53, and is integrally molded as a whole by pressing. The umbrella-like portion 54 is formed in substantially the same shape as the inside of the top portion of the case 60 .

Below the bushing member 33 of the valve shaft 41, the valve shaft holder 6, which forms a threaded connection A with the valve shaft 41 as will be described later and has the function of suppressing the inclination of the valve shaft 41, is mounted on the valve body 30. It is non-rotatably fixed relative to the

The valve shaft holder 6 is made of, for example, a resin material such as polyphenylene sulfide (PPS), and contains an additive to reduce the coefficient of friction. As the additive, a fluororesin such as polytetrafluoroethylene (PTFE), carbon fiber, or the like is used.

The valve shaft holder 6 includes an upper cylindrical small diameter portion 6a, a lower cylindrical large diameter portion 6b, a fitting portion 6c accommodated in the inner peripheral side of the valve main body 30, and a ring-shaped flange portion 6f. consists of The flange portion 6f of the valve shaft holder 6 is fixed to the upper end of the valve body 30 by welding or the like. Further, inside the valve shaft holder 6, a housing chamber 6h is formed for housing a valve guide 18, which will be described later.

A female screw 6d is formed downward to a predetermined depth from an upper opening 6g of the cylindrical small diameter portion 6a of the valve shaft holder 6. As shown in FIG. Therefore, in this embodiment, the valve stem holder 6 functions as a female screw member. A male thread 41a formed on the outer periphery of the valve stem 41 and a female thread 6d formed on the inner periphery of the cylindrical small-diameter portion 6a of the valve stem holder 6 form a screw connection A.

Further, a pressure equalizing hole 51 is formed in the side surface of the cylindrical large diameter portion 6b of the valve shaft holder 6, and the valve shaft holder chamber 83 in the cylindrical large diameter portion 6b and the rotor are separated by the pressure equalizing hole 51. It communicates with the housing chamber 67 (second back pressure chamber). By providing the pressure equalizing hole 51 in this way, the space in the case 60 for accommodating the rotor 4 and the space in the valve shaft holder 6 are communicated with each other, so that the movement of the valve shaft holder 6 can be performed smoothly. can.

Further, a cylindrical valve guide 18 is disposed below the valve shaft 41 so as to be slidable with respect to the housing chamber 6h of the valve shaft holder 6. As shown in FIG. The valve guide 18 is bent at a substantially right angle on the side of the ceiling portion 21 by press molding. A through hole 18 a is formed in the ceiling portion 21 . A flange portion 41b is further formed below the valve shaft 41. As shown in FIG.

Here, the valve shaft 41 is inserted loosely through the through hole 18a of the valve guide 18 so as to be rotatable with respect to the valve guide 18 and displaceable in the radial direction. It is positioned within the valve guide 18 so as to be rotatable relative to the guide 18 and radially displaceable. Further, the valve shaft 41 is inserted through the through hole 18a, and the upper surface of the collar portion 41b is arranged so as to face the ceiling portion 21 of the valve guide 18. As shown in FIG. It should be noted that the valve stem 41 is prevented from slipping out by the collar portion 41b having a diameter larger than that of the through hole 18a of the valve guide 18. As shown in FIG.

Since the valve shaft 41 and the valve guide 18 are movable relative to each other in the radial direction, the valve shaft holder 6 and the valve shaft 41 are not required to have a very high degree of concentric mounting accuracy. Concentricity with the valve body 17 is obtained.

Between the ceiling portion 21 of the valve guide 18 and the flange portion 41b of the valve shaft 41, a washer 70 having a through hole formed in the center thereof is installed. The washer 70 is preferably a metal washer with a highly slippery surface, a highly slippery resin washer such as fluororesin, a metal washer coated with a highly slippery resin, or various resin washers containing a highly slippery resin.
Further, a compressed valve spring 27 and a spring retainer 35 are housed within the valve guide 18 .

Next, the dimensional relationship of the parts constituting the motor-operated valve 2, which is the main point of the present invention, will be described. FIG. 2 is an enlarged cross-sectional view of the screw connection A portion of the electrically operated valve 2 according to the embodiment. As shown in FIG. 2, a male thread 41a is formed on the outer periphery of the valve shaft 41 at the connection A portion, and a female thread 6d is formed on the inner periphery of the cylindrical small diameter portion 6a of the valve shaft holder 6. . The inner diameter of the female screw 6d is designed to be larger than the outer diameter of the male screw 41a. A radial clearance 66 is formed between them.

Moreover, FIG. 3 is an enlarged cross-sectional view of the portion shown within the circle B in FIG. 1 in the electric valve 2 according to the embodiment. As shown in FIG. 3, no screw is formed on the outer periphery 41o of the valve shaft 41 at the portion penetrating the through hole 33a, and the inner periphery 33i of the through hole 33a of the bushing member 33 and the outer periphery 41o of the valve shaft 41 are not threaded. A gap 34 exists between them. This gap 34 is formed narrower than the clearance 66 . That is, the difference between the inner diameter of the through hole 33a and the outer diameter of the valve stem 41 (male screw member) is set to be smaller than the smaller of the following differences (1) and (2). formed.

(1) The thread diameter of the male thread 41a of the valve stem 41 (male thread member) (the outer diameter of the thread thread 41m) and the root diameter of the female thread 6d of the valve stem holder 6 (female thread member) (the inner periphery of the thread root 6v) (2) The root diameter (peripheral diameter of thread root 41v) of the male thread 41a of the valve stem 41 (male thread member) and the thread diameter of the female thread 6d of the valve stem holder 6 (female thread member) Furthermore, FIG. 4 is an enlarged cross-sectional view of the portion shown within the circle C in FIG. 1 in the electric valve 2 according to the embodiment. As shown in FIG. 4 , in the motor operated valve 2 , a gap 68 wider than the clearance 66 exists between the inner circumference 60 i of the case 60 and the outer circumference 4 o of the rotor 4 . That is, the difference between the inner diameter of the case 60 and the outer diameter of the rotor 4 is set to be larger than the larger one of the differences (1) and (2).

According to the motor operated valve 2 of this embodiment, the gap 34 between the through hole 33a of the bushing member 33 and the valve shaft 41 is narrower than the clearance 66 between the male screw 41a and the female screw 6d. , the eccentricity of the rotor 4 with respect to the axis can be suppressed when the rotor 4 rotates. Therefore, the rotor 4 can be properly rotated, and the electric valve 2 having high operability can be provided.

As described above, the valve stem holder 6 (female screw member) is made of resin such as polyphenylene sulfide (PPS), and therefore has a low coefficient of friction and excellent durability. On the other hand, precision molding is difficult for resin parts that are generally molded by injection molding, considering dimensional deformation such as sink marks and warping due to injection molding, and dimensional changes peculiar to resin molding such as linear expansion and swelling. often.

Therefore, when the valve stem holder 6 made of resin is employed, there is a tendency that the clearance 66 generated in the engagement between the male thread 41a and the female thread 6d tends to become large. If the clearance 66 becomes large, as shown in FIG. 5, not only the rotor 4 but also the valve shaft 41 (male threaded member) may rotate around a biased axis.

However, by making the gap 34 between the through hole 33a of the bushing member 33 and the valve shaft 41 narrower than the clearance 66 between the male screw 41a and the female screw 6d, the eccentricity of the rotor 4 can be suppressed. Therefore, when the valve shaft holder 6 (female screw member) is made of resin in the motor-operated valve 2, the effect of reducing the influence on the operability is remarkable.

Further, according to the electrically operated valve 2 according to the embodiment, the gap 68 between the inner circumference of the case 60 and the outer circumference of the rotor 4 is widened to be larger than the clearance 66, so that the rotor 4 is moved from the case when the rotor 4 rotates. 60 to prevent the rotor 4 from sliding on the inner peripheral surface of the case 60 . Therefore, the rotor 4 can be properly rotated with high accuracy.

Here, when the valve shaft holder 6 made of resin is used, the clearance 66 between the male screw 41a and the female screw 6d becomes large, and as shown in FIG. It is also conceivable that the rotor 4 contacts the case 60 (see circle F) and the rotation of the rotor 4 is hindered.

However, by widening the gap 68 (see FIG. 4) between the inner circumference of the case 60 and the outer circumference of the rotor 4 and making the gap 68 larger than the clearance 66, the valve stem holder 6 (female screw member) is made of resin. The rotor 4 can be prevented from coming into contact with the case 60 even if the case 60 does.

It should be noted that the gap 68 between the rotor 4 and the case 60 need not be excessively wide. Therefore, even if the gap 68 between the rotor 4 and the case 60 is widened, if the gap 68 can be maintained at a predetermined distance or less, the air gap between the rotor 4 and the coils can be kept small, and torque can be prevented from decreasing. can be reduced.

Further, in the motor operated valve 2 of the present embodiment, the case where the bush member 33 is a separate member from the rotor 4 has been described as an example, but the rotor 4 and the bush member 33 are formed as one member. may be Also in this case, the rotation of the rotor 4 is transmitted to the valve shaft 41 .

Further, in the motor operated valve 2 of the present embodiment, the case where the valve shaft holder 6 (female screw member) is made of resin has been described as an example, but the valve shaft holder 6 is made of metal. may Even if the valve shaft holder 6 is made of metal, if the clearance 66 between the male screw 41a and the female screw 6d is large, narrowing the gap 34 between the through hole 33a of the bushing member 33 and the valve shaft 41 , the eccentricity of the rotor 4 with respect to the axial center can be suppressed when the rotor rotates.

The motor-operated valve 2 of the present embodiment is used as an expansion valve provided between the condenser and the evaporator in a refrigeration cycle system including, for example, a compressor, a condenser, an expansion valve, and an evaporator. .

2 Motor-operated valve 4 Rotor 4o Outer circumference of rotor 6 Valve stem holder 6a Cylindrical small diameter portion 6d Female screw 6m Female screw thread 6v Female screw root 17 Valve body 33 Bushing member 33a Through hole 33i Inner circumference of through hole 34 Gap 41 Valve stem 41a Male thread 41c Welding 41m Male thread thread 41o Valve stem outer periphery 41v Male thread root 60 Case 60i Case inner periphery 66 Clearance 68 Gap

Claims (6)

Rotational motion of the rotor accommodated in the inner circumference of the case is converted into linear motion by threading the male thread of the male thread member and the female thread of the female thread member, and is accommodated in the valve body based on this linear motion. A motor-operated valve that axially moves a valve element with a
The female screw member is made of resin,
The rotor is made of resin containing magnetic powder,
a cylindrical bushing member formed with a through hole through which the male threaded member is fixed and transmitting the rotation of the rotor to the male threaded member;
The male screw member is threadedly engaged with the female screw member in a state where one end on the rotor side is free with respect to the through hole of the bush member,
A welding region is formed between the end surface of the end portion where the outer circumference of the bushing member is reduced in diameter and the side surface of the male screw member protruding from the bushing member,
A gap is formed between the bushing member and the male threaded member, and the bushing member is fixed to the male threaded member by welding,
The difference between the inner diameter of the through hole and the outer diameter of the male screw member is
a difference between the thread diameter of the male thread of the male thread member and the root diameter of the female thread of the female thread member ;
A motor-operated valve, wherein the difference between the root diameter of the male screw of the male screw member and the crest diameter of the female screw of the female screw member is smaller than the smaller one. A tubular valve guide disposed on the side of the male screw member on which the valve body is located,
2. The motor-operated valve according to claim 1, wherein the bush member is welded to the male screw member at an end opposite to the side where the valve body is located. the outer diameter of the bushing member and the outer diameter of the valve guide are larger than the thread diameter of the female thread of the female thread member;
3. The motor-operated valve according to claim 2, wherein a portion connecting the male screw member and the valve guide is housed in a housing chamber housing the valve guide in the female screw member. The difference between the inner diameter of the case and the outer diameter of the rotor is
The difference between the ridge diameter of the male thread of the male thread member and the root diameter of the female thread of the female thread member, and the difference between the root diameter of the male thread of the male thread member and the ridge diameter of the female thread of the female thread member. 4. The motor-operated valve according to any one of claims 1 to 3, which is larger than whichever is larger. The electrically operated valve according to any one of claims 1 to 4, wherein the female screw member is made of resin. A refrigeration cycle system comprising a compressor, a condenser, an expansion valve, and an evaporator, wherein the motor-operated valve according to any one of claims 1 to 5 is used as the expansion valve. .

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