JP5654918B2 - Motorized valve - Google Patents

Description

  The present invention relates to a motor-operated valve, and more particularly to a motor-operated valve that is used for refrigerant flow control in a refrigeration cycle system and configured to press-fit a stem into a valve body.

  As an electric valve used for the flow rate control of the refrigerant, a valve body is disposed in a valve body having a valve chamber and a valve seat, and a stem (valve rod) for operating the valve body is disposed in the bellows. An electric valve having a structure for sealing between the valve and the stem is disclosed in Patent Document 1. In this type of electric valve, the electric motor and the gear reduction device are sealed inside a metal cylindrical can, and the invasion of moisture from the outside is prevented by a seal structure using baking rubber or the like. The rotational output of the gear reduction device is converted into a linear motion by a screw mechanism and transmitted to the stem.

  In the motor-operated valve having the above structure, the stem is formed to have a considerably small diameter as compared with the valve body. Therefore, when the valve body and the stem are integrally structured, a lot of material is wasted by machining. Therefore, as shown in FIG. 1, the stem 6 and the valve body 5 are separated from each other, and the stem 6 is press-fitted into the valve body 5 to integrate them.

  Here, as shown in FIG. 1, when the stem 6 is press-fitted into the concave portion 5 a at the upper portion of the valve body 5, it communicates with the concave portion 5 a of the valve body 5 so as to improve the stability and reliability of the press-fit portion. At the same time, holes 5b and 5c (first hole 5b and second hole 5c) opened on the lower surface are formed to release air when the stem 6 is press-fitted. Here, the inner diameter of the first hole 5b is about half of the inner diameter of the second hole 5c, and the length (depth) of the first hole 5b is significantly shorter than the length of the second hole 5c. Yes.

  The motor-operated valve 1 has a valve body 2 having a valve seat 4 and a valve chamber 3, and an inflow pipe 7 and an outflow pipe 8 are connected to the valve body 2 so as to communicate with the valve chamber 3. In the valve chamber 3 contacts and separates from the valve seat 4 to change the flow path area. In FIG. 1, only main parts are hatched.

  A bellows 10 and a stem 6 inserted inside the bellows 10 are disposed in an inner diameter portion 9 communicating with the valve chamber 3 of the valve body 2, and a lower end portion of the bellows 10 is fixed to the stem 6. The upper end of 10 is fixed to the valve body 2 via a ring member 17. A guide member 11 having an internal thread portion 11 a is disposed on the upper portion of the valve body 2, and is fixed to the valve body 2 with a cap nut 21.

  The lower end portion of the screw rod 12 having the male screw portion 12a that is screwed into the female screw portion 11a of the guide member 11 presses the transmission member 20 on the upper portion of the stem 6 via the ball 18 and moves the stem 6 in the axial direction. A seal member 14 made of baking rubber and a metal plate 13 are disposed on the guide member 11.

  A base 22 is placed on the plate 13, and is fixed in the can 23 by caulking the lower end portion of the flange portion 23 a of the can 23 covering the outer periphery. An excitation device 16 comprising a stator and its excitation coil is placed on the upper portion of the base 22, and power is supplied through a lead wire 25. The lead wire 25 is inserted into a lead wire support portion 26 integral with the sealing member 14 made of baking rubber and sealed with an adhesive 27. The rotor 15 disposed inside the excitation device 16 is driven by a pulse current applied to the excitation device 16. The rotor 15 is connected to the screw rod 12 through a gear train 28.

  With the above configuration, the output of the electric motor is transmitted to the screw rod 12 via the rotor 15 and the gear train 28, and the screw rod 12 performs a linear motion by the screw mechanism according to the given rotation, and via the stem 6. The valve body 5 is moved up and down, and the flow rate of the fluid passing through the valve chamber 3 is controlled in accordance with the flow path area formed between the valve body 5 and the valve seat 4.

JP 2006-177503 A

  However, when the motor-operated valve 1 is used for refrigerant flow control in a refrigeration cycle system or the like, the refrigerant is full in the inflow pipe 7 and the outflow pipe 8, and the difference between the inflow pipe 7 and the outflow pipe 8. When the pressure is low (about 0.1 to 0.3 MPa), there is a problem that a whistling sound (high frequency sound, hereinafter referred to as “abnormal noise”) is generated.

  Therefore, the present invention has been made in view of the problems in the above-described conventional technology, and an object thereof is to provide an electric valve that does not generate abnormal noise even under the above-described conditions.

  In order to achieve the above object, the present invention comprises a stem that moves linearly as the rotor of an electric motor rotates, and a valve body that is press-fitted into the stem and integrated with the stem, The valve body is a motor-operated valve that controls a valve opening degree of the valve seat, wherein the valve body has a concave portion for press-fitting the stem in an upper portion, and a first hole portion that communicates with the concave portion and extends in the vertical direction. And a second hole having a diameter larger than that of the first hole, and an inverted cone having an outer diameter that gradually increases upward from the lower surface. A depth of the second hole portion is 5.0 mm or less, and the distance between the outer peripheral edge portion of the lower surface and the opening edge portion of the second hole portion is 0.7 mm or more. It is characterized by.

  According to the present invention, the depth of the second hole portion of the valve body is 5.0 mm or less, and the distance between the outer peripheral edge portion of the lower surface and the opening edge portion of the second hole portion is 0.7 mm or more. Even when the refrigerant is full in the inflow pipe and the outflow pipe connected to the valve chamber and the differential pressure between the inflow pipe and the outflow pipe is low, the generation of abnormal noise can be prevented. .

  In the motor-operated valve, an apex angle of the inverted truncated cone portion can be set to 120 degrees, and an inner diameter of the second hole portion can be set to 2 mm.

  As described above, according to the present invention, even when the refrigerant is full in the inflow pipe and the outflow pipe connected to the valve chamber, and the differential pressure between the inflow pipe and the outflow pipe is low, It is possible to provide an electric valve that can prevent the generation of abnormal noise.

It is sectional drawing which shows the motor operated valve concerning the past and one Example of this invention. (A) is an enlarged sectional view showing the valve body of the motor-operated valve shown in FIG. 1 and the vicinity thereof, (b) is an enlarged view of the lower end portion of the valve body shown in (a), and (a) and (B) Both are drawn with hatching omitted. It is a graph which shows the relationship between the frequency at the time of using this invention and the conventional valve body, and a sound pressure. It is a graph which shows the relationship between the frequency at the time of using this invention and the conventional valve body, and acceleration.

  In order to achieve the above object, the present inventors first confirmed that when the second hole portion 5c formed in the valve body 5 is closed, the abnormal noise disappears in terms of hearing.

  However, as described above, the holes 5b and 5c are indispensable for press-fitting the stem 6 into the valve body 5, and therefore cannot be erased.

  Therefore, as a result of performing an experiment with various changes in the depth and the like of the second hole portion 5c, the depth L1 of the second hole portion 5c of the valve body 5 is finally set to 5.0 mm as shown in FIG. Hereinafter, the inflow pipe 7 and the outflow pipe 8 connected to the valve chamber 3 are set such that the distance L2 between the outer peripheral edge 5e of the lower surface 5d and the opening edge 5f of the second hole 5c is 0.7 mm or more. Even when the refrigerant is full and the pressure difference between the inflow pipe 7 and the outflow pipe 8 is low, it has been confirmed that no abnormal noise is generated for hearing. The dimensions of the valve body 5 and the vicinity thereof are summarized as follows. The parentheses indicate conventional ones, and the dimensions without parentheses indicate the same as the conventional ones. Dimensions that are not described below are also the same as in the prior art.

(1) Inner diameter of second hole 5c: 2 mm, depth L1: 5.0 mm or less (8.2 mm)
(2) Distance L2 between the outer peripheral edge 5e of the lower surface 5d of the valve body 5 and the opening edge 5f of the second hole 5c: 0.7 mm or more (0.2 mm)
(3) 120 ° apex angle of the inverted frustoconical portion 5g continuous with the outer peripheral edge portion 5e of the lower surface 5d of the valve body 5 (4) Diameter of the valve seat 4: 5.2 mm to 6.4 mm
(5) The fluid flows into the valve chamber 3 from the side surface of the valve body 5.

  Note that the diameter of the valve seat 4 is 5.2 mm to 6.4 mm because the diameter changes according to the flow rate of the fluid (refrigerant).

  Next, experimental results using the valve body 5 having the above dimensions will be described.

  Table 1 shows that the diameter of the valve seat 4 is 5.2 mm, the depth L1 of the second hole 5c, and the outer peripheral edge 5e of the lower surface 5d of the valve body 5 and the opening edge 5f of the second hole 5c. The above-mentioned dimensions other than the distance L2 between them are fixed, and the presence or absence of abnormal noise when the depth L1 and the distance L2 are changed within the range of the differential pressure of 0.1 to 0.3 MPa is shown.

  According to the table, when the depth L1 is 5.0 mm or less and the distance L2 is 0.7 mm or more, no abnormal noise is generated for hearing, and in other cases, abnormal noise is generated. I understand.

FIG. 3 shows a conventional product (comparative example) having the above-mentioned dimensions with a diameter of the valve seat 4 of 5.2 mm, and an embodiment of the present invention (depth L1 = 5 mm, distance L2 = 0.7 mm). 1 shows the relationship between the frequency (Hz) and sound pressure (dB) of the sound generated when a fluid is flowed.
As shown in the figure, in the comparative example, the sound pressure near the frequency of 10 kHz is high, and in the embodiment, the sound pressure in this region is reduced. From this, it can be inferred that, in the example, the abnormal sound disappeared from the viewpoint of hearing by reducing the sound pressure in the vicinity of the frequency of 10 kHz.

FIG. 4 shows the results of measuring the frequency (Hz) and acceleration (m / s ² ) in the comparative example and the example by applying an accelerometer pickup to the valve body 2. The acceleration data on the vertical axis in the figure indicates an increase / decrease value when a predetermined acceleration is set to “0”.
As shown in the figure, it can be seen that the acceleration in the vicinity of the frequency of 10 kHz is high in the comparative example, and the acceleration in this region is reduced in the example.

  Although the above experiment was performed only when the diameter of the valve seat 4 was 5.2 mm, the cause of abnormal noise is that the refrigerant enters the second hole 5c at the center from the periphery of the valve body 5. Therefore, it is considered that the diameter of the valve seat 4 hardly affects the presence or absence of abnormal noise. For the same reason, it is considered that the outer diameter of the valve body 5 and the inner diameters of the inflow pipe 7 and the outflow pipe 8 hardly affect the generation of noise.

DESCRIPTION OF SYMBOLS 1 Motorized valve 2 Valve body 3 Valve chamber 4 Valve seat 5 Valve body 5a Recessed part 5b 1st hole part 5c 2nd hole part 5d Lower surface 5e Outer peripheral edge part 5f Opening edge part 5g Reverse frustoconical part 6 Stem 7 Inflow pipe 8 Outflow Tube 9 Inner diameter portion 10 Bellows 11 Guide member 11a Female thread portion 12 Screw rod 12a Male thread portion 13 Plate 14 Seal member 15 Rotor 16 Excitation device 17 Ring member 18 Ball 20 Transmission member 21 Cap nut 22 Base 23 Can 23a Flange portion 25 Lead wire 26 Lead wire support 27 Adhesive 28 Gear train

Claims (3)

An electric motor that includes a stem that moves linearly as the rotor of the electric motor rotates, and a valve body that is press-fitted into the stem and integrated with the stem, and controls the valve opening of the valve body with respect to the valve seat. A valve,
The valve body is
A recess for press-fitting the stem at the top;
A first hole that communicates with the recess and extends vertically.
Communicating with the first hole, opening on the lower surface of the valve body, a second hole having a larger diameter than the first hole;
An inverted frustoconical portion whose outer diameter continuously increases gradually from the lower surface upward,
The motor-operated valve, wherein a depth of the second hole portion is 5.0 mm or less, and a distance between an outer peripheral edge portion of the lower surface and an opening edge portion of the second hole portion is 0.7 mm or more.   The motor-operated valve according to claim 1, wherein an apex angle of the inverted truncated cone portion is 120 degrees.   The motor-operated valve according to claim 1 or 2, wherein an inner diameter of the second hole portion is 2 mm.

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