JP2013224708A - Motor-operated valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To set an equal pressure path, for connecting a back space with a secondary side port with respect to a valve member, to be large in passage sectional area in a pressure balanced type motor-operated valve.SOLUTION: A cylindrical valve guide 2 is disposed in the valve chamber 1A of a valve body 1. A valve member 3 is disposed to be slidable in the valve guide 2. The valve member 3 is held by a connection rod 4 penetrating a cap member 5 and a male screw shaft 51. The connection rod 4 is connected to the magnet rotor 62 of a stepping motor 6. A female screw member 63 fixed to the magnet rotor 62 is screwed with the male screw shaft 51. A valve body 31 of the valve member 3 is formed into a cylindrical shape to be slidable in the guide surface 2a of the valve guide 2, and a needle part is eliminated. A tapered seating surface 21b is formed in a valve seat 21 defining a valve port 21a. An annular coupling part 22 defining a primary side port 11a is formed in the valve guide 21. The valve guide 2 is integrally fixed to the valve body 1 by the coupling part 22. An equal pressure path 1A2 is made to connnect a part around the valve guide 2 of the valve chamber 1A to a back space 1A1.

Description

  The present invention relates to a motor-operated valve for use in a refrigeration cycle, and more particularly to a pressure balance type motor-operated valve.

  Conventionally, as this kind of motor-operated valve, there are ones disclosed in, for example, Japanese Patent Laid-Open No. 2000-320711 (Patent Document 1) and Japanese Patent No. 3672380 (Patent Document 2). FIG. 5 is a longitudinal sectional view of a conventional motor-operated valve equivalent to Patent Document 2. This conventional electric valve includes a valve body a and a stepping motor b. The valve body a is formed with a primary port a1, a secondary port a2, a valve chamber a3, and a guide mounting hole a4. A cylindrical valve guide c is fitted into the guide mounting hole a4, and a valve body d1 of the valve member d is slidably disposed in the valve guide c. A primary side joint pipe e1 is communicated with the primary side port a1. A secondary side joint pipe e2 communicates with the secondary side port (valve port) a2. The valve member d is held by a connecting rod f, and the connecting rod f is connected to the magnet rotor b1 of the stepping motor b.

  The valve guide c is formed by integrally forming a cylindrical guide portion c1 and a lid portion c2, and a male screw shaft c3 through which the connecting rod f passes is fixed to the lid portion c2. The male screw shaft c3 is screwed with a female screw member b2 fixed to the magnet rotor b1 of the stepping motor b. The driving of the stepping motor b causes the connecting rod f and the valve member d to move up and down. The valve member d is separated / seats with respect to the valve seat a5 around the secondary port a2. The valve member d includes a substantially cylindrical valve body d1 and a saddle type packing d2 that is in sliding contact with the valve guide c. A needle part d12 having a tapered surface d11 is provided at the end of the valve body d1 on the valve seat part a5 side.

  A space between the valve member d and the lid c2 in the valve guide c is a back space a31, and the back space a31 is electrically connected to the secondary port a2 through the valve member d. Thereby, the pressure balance between the fluid pressure acting on the front surface of the valve member d and the fluid pressure in the back space a31 is achieved, and the driving force of the stepping motor b when moving the valve member d up and down is reduced.

  FIG. 6 is a view showing a main part of the above-described conventional electric valve assembly process. First, as shown in FIG. 6 (A), an assembly comprising a valve member d and a connecting rod f is formed. Next, as shown in FIG. 6B, the connecting rod f is inserted from the inside of the valve guide c into the lid c2 integrated with the valve guide c, and the valve member d is inserted into the valve guide c. Then, as shown in FIG. 3C, the valve guide c is fitted into the guide mounting hole a4 of the valve main body a, and the lid c2 is screwed into the valve main body a.

JP 2000-320711 A Japanese Patent No. 3672380

  In the conventional motor-operated valve, the tapered surface d11 is formed on the needle part d12 of the valve body d1 seated on the valve seat part a5. In order to balance the pressure, the inner diameter of the secondary port a2 of the valve seat portion d and the inner diameter of the guide surface c1 of the valve guide c with which the saddle type packing d2 is slidably contact are made substantially the same size. For this reason, it is necessary to make the outer diameter of the needle part d12 of the valve body d1 larger than the inner diameter of the guide surface c1, and make the inner diameter of the guide mounting hole a4 of the valve body a larger than the outer diameter of the needle part d12.

  Therefore, it is difficult to provide a pressure equalizing path in the valve body a. In addition, since the back space a31 with respect to the valve member d is covered with the valve guide c, it is necessary to provide a pressure equalizing path that connects the back space a31 and the secondary port a2 inside the valve member d. This results in a pressure equalizing path with a small passage area. When the passage area of the pressure equalizing path is small, there is a problem that the pressure balance is easily broken. Further, there is a problem that the valve member d is likely to float when a water hammer from the secondary side to the primary side is generated.

  The present invention has been made in order to solve the above-described problems, and in a pressure balance type electric valve, a pressure equalizing path that connects the back space with respect to the valve member and the secondary port is provided with a passage cross-sectional area. The challenge is to make it big.

  The motor-driven valve according to claim 1 is a valve main body in which a valve chamber is formed, a cylindrical valve guide disposed in the valve main body, a slidably disposed in the valve guide, and a valve seat. A valve member that opens and closes a valve port defined by: an electric motor attached to the valve body; and a valve rod that holds the valve member and is coupled to the electric motor, the valve rod being driven by the electric motor The valve member is moved in the axial direction to open and close the valve port by the valve member, and the fluid pressure in the back space with respect to the valve member of the valve chamber and the valve port is sealed by a seal member provided in the valve member. In the motor-operated valve adapted to achieve a pressure balance with the fluid pressure, an annular coupling portion defining a primary port is formed on a side portion with respect to the axis line of the valve guide, and a secondary port of the valve guide is formed. Opposite opening A valve seat portion defining a valve port is formed at an end portion, and the valve seat portion has a tapered seating surface facing the inside of the valve guide around the valve port, and the valve guide of the valve member The valve body that is slidably contacted is a cylindrical valve body that can be inserted into the guide surface of the valve guide from the side opposite to the valve seat portion of the valve guide, and whose outer peripheral end can contact the seating surface. The valve guide is disposed in the valve chamber of the valve body, and the primary port is connected to a primary side joint pipe provided in the valve body so that the valve guide is connected via the coupling portion. Is formed integrally with the valve body.

  The motor-driven valve according to claim 2 is the motor-operated valve according to claim 1, wherein the valve guide and the valve main body are integrally formed by brazing or MIM (Metal Injection Molding) at the coupling portion. It is characterized by being.

  According to the motor-driven valve of the first aspect, the valve guide is integrally fixed to the valve body so that the valve guide communicates with the primary side joint pipe through the primary side port in the valve chamber. Since there is no extra member such as a fixing screw in the back space of the guide, a pressure equalizing path having a large passage area communicating with the back space can be configured using the valve chamber.

  According to the electric valve of the second aspect, in addition to the effect of the first aspect, the valve guide and the valve main body can be easily integrated.

It is a longitudinal cross-sectional view of the valve closed state of the electric valve of the embodiment of the present invention. It is a principal part expanded sectional view of the motor operated valve of embodiment of this invention. It is a figure which shows a part of assembly | attachment process of the motor operated valve of embodiment of this invention. It is a figure explaining the effect | action at the time of abrasion of the valve seat in the motor operated valve of embodiment of this invention compared with a prior art example. It is a longitudinal cross-sectional view which shows an example of the conventional motor operated valve. It is a figure which shows a part of assembly | attachment process of the conventional motor operated valve.

  Next, an embodiment of the motor-operated valve of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a motor-operated valve according to the embodiment in a closed state, and FIG. Note that the concept of “upper and lower” in the following description corresponds to the upper and lower sides in the drawings of FIGS. 1 and 2. The motor-operated valve according to this embodiment has a cylindrical valve body 1, and a cylindrical cylinder-shaped valve chamber 1 </ b> A is formed in the valve body 1. A hollow cylindrical valve guide 2 is disposed in the valve chamber 1A. A primary port 11 a is formed in the valve guide 2, and the primary port 11 a communicates with a primary joint pipe 11 that penetrates the side surface of the valve body 1. A secondary port 1a is formed at the lower end of the valve chamber 1A in the direction of the axis L, and this secondary port 1a communicates with the secondary joint pipe 12.

  A valve seat portion 21 is formed at the end of the valve guide 2 on the secondary joint pipe 12 side, and the valve seat portion 21 defines a circular valve port 21a that conducts the valve guide 2 and the valve chamber 1A. doing. A tapered seating surface 21b is formed around the opening periphery of the valve port 21a, and a later-described valve body 31 is seated on the seating surface 21b. The valve guide 2 has an annular coupling portion 22 that forms the outer periphery of the primary port 11a. The valve guide 2 is integrally fixed to the valve body 1 by brazing in a state where the coupling portion 22 is fitted to the joint pipe 11 and is in contact with the lower inner wall of the valve chamber 1A. The valve body 1 and the valve guide 2 may be integrally molded by, for example, MIM (Metal Injection Molding).

  A valve member 3 is slidably disposed in the valve guide 2. The valve member 3 is in sliding contact with the inner guide surface 2 a of the valve guide 2 and is slidable in the direction of the axis L with respect to the valve guide 2. The valve member 3 has a hollow cylindrical valve body 31, and the valve body 31 has an outer peripheral surface 31 a that is in sliding contact with the guide surface 2 a of the valve guide 2. Further, a bearing 32 is provided in the valve body 31. The valve body 31 is held by the connecting rod 4 via the bearing 32. The inner ring of the bearing 32 is attached to the connecting rod 4 with a certain amount of play, and the outer ring is also attached to the valve body 31 with a certain amount of play.

  Further, in the valve body 31, a first coil spring 33 is mounted between the outer ring of the bearing 32 and a spring receiver 33 a formed on the inner wall of the valve body 31, and the valve body 31 is attached to the valve seat portion 21. Energized in the direction. A second coil spring 34 is mounted between the inner ring of the bearing 32 and the connecting rod 4 via an upper spring receiver 34a and a lower spring receiver 34b attached to the lower end of the connecting rod 4. The connecting rod 4 is urged toward the inner ring of the bearing 32. Further, the upper cylindrical portion 31 a of the valve body 31 is provided with a saddle type packing 35 that is a seal member for sealing between the peripheral surface of the valve body 31 and the guide surface 2 a of the valve guide 2. When the valve member 3 moves inside, it slides in the valve guide 2.

  The connecting rod 4 extends through a lid member 5 that covers the upper portion of the valve body 1 and a male screw shaft 51 fixed to the lid member 5 to a stepping motor 6 as an “electric motor”. A plurality of conduction holes 5a are formed in the lid member 5, and fluid such as a refrigerant can flow into the stepping motor 6 from the valve chamber 1A through the conduction holes 5a. The connecting rod 4 is formed in a rod shape with a circular cross section. The male screw shaft 51 has a male screw portion 51a on the outer periphery and a through hole 51b on the axis L, and the connecting rod 4 can slide in the through hole 51b in the direction of the axis L. A spring receiver 43 a that receives the third coil spring 43 is attached to the uppermost portion of the connecting rod 4.

  A case 61 of the stepping motor 6 is airtightly fixed to the upper end of the valve main body 1 via a fixing member 13 by welding or the like. In the case 61, a magnet rotor 62 having a magnetized portion 62a on its outer periphery is rotatably provided. A coil spring 43 is mounted between the magnet rotor 62 and the spring receiver 43a to urge the connecting rod 4 toward the female screw member 63 side. A stator coil 64 is disposed on the outer periphery of the case 61, and the stepping motor 6 rotates the magnet rotor 62 according to the number of pulses when a pulse signal is given to the stator coil 64. In addition, the rotation stopper mechanism 7 by the movable stopper member 72 kicked around by the spiral guide wire 71 and the collar 62b of the magnet rotor 62 is provided in the ceiling part of the case 61.

  With the above configuration, when the stepping motor 6 is driven, the connecting rod 4 and the valve member 3 are moved up and down in the direction of the axis L by the screw feeding mechanism of the male screw shaft 51 and the female screw member 63, and the valve element 31 is guided to the valve guide 2. Then, the valve seat 2 formed on the valve guide 2 is separated from / seated. Thereby, the valve port 21a is opened and closed. When the valve body 31 is seated on the valve seat portion 21, the end portion of the outer peripheral surface 31a of the valve body 31 on the valve seat portion 21 side comes into contact with the seating surface 21b.

  In the valve chamber 1 </ b> A, the space on the lid member 5 side of the valve member 3 is a back space 1 </ b> A <b> 1 with respect to the valve member 3. In addition, in the valve chamber 1A, the periphery of the valve guide 2 is a pressure equalizing path 1A2 having a large passage area. Thereby, the pressure of the fluid in the secondary side port 1a and the valve port 21a and the pressure of the fluid in the back space 1A1 are always equalized by the pressure equalizing path 1A2. Moreover, the change of the pressure of the fluid in the secondary side port 1a and the valve port 21a is instantaneously transmitted as the pressure of the fluid in the back space.

  Further, the outer diameter D1 of the valve body 31 and the inner diameter D2 of the valve guide 2 in which the saddle type packing 35 is in sliding contact are substantially the same size. Therefore, the pressure balance between the fluid pressure acting on the front surface of the valve member 3 and the fluid pressure in the back space 1A1 can be achieved, and the driving force of the stepping motor 6 can be reduced. Since the pressure equalizing path 1A2 has a large passage area, it is easy to achieve a pressure balance.

  Drawing 3 is a figure showing the important section of the assembly process of the electric valve of an embodiment. First, as shown in FIG. 3 (A), an assembly comprising the valve member 3 and the connecting rod 4 is formed. Next, as shown in FIG. 3 (B), the portion of the valve member 3 is inserted into the guide hole 2 a from the opposite side of the valve seat portion 21 of the valve guide 2 integrated with the valve body 1. Then, as shown in FIG. 3 (B), the connecting rod 4 is inserted into the male screw shaft 51 and the lid member 5 is screwed into the valve body 1.

  Thus, in the valve chamber 1A, the valve guide 2 is integrally fixed to the valve body 1 so as to communicate with the primary side joint pipe 11 via the primary side port 11a. There is no need to fix the lid member 5 side of the valve guide 2. That is, there is no extra member like the conventional screw member between the valve guide 2 and the lid member 5. Therefore, by using the valve chamber 1A around the valve guide 2, the pressure equalizing path 1A2 having a large passage area communicating with the back space 1A1 can be configured.

  The valve body 31 has a cylindrical shape without a needle portion as in the prior art, and a tapered seating surface 21a is formed on the valve seat 21 side. Thereby, the pressure balance can be stabilized even when the valve seat 21 is worn. 31 is made of stainless steel, for example, and the valve seat 21 (valve guide 2) is made of brass, for example, and the valve seat 21 may be worn by long-term use of the electric valve. As shown in FIG. 4A, before the valve seat 21 is worn, the diameter of the contact portion between the valve body 31 and the valve seat 21 when the valve body 31 is seated, that is, the seal diameter D1, is the outer diameter D1 of the valve body 31. In addition, even when the valve seat 21 is worn, the seal diameter D1 is the same as before wear, and the pressure balance does not change even if the valve seat 21 is worn.

  On the other hand, as shown in FIG. 4B, the seal diameter D2 before the wear of the conventional valve seat a5 is changed to the seal diameter D2 ′ when the valve seat a5 is worn. At least the contact portion between the valve seat a5 and the needle portion d12 becomes indefinite within the range of x, and the pressure balance changes. Such a change in pressure balance does not occur in the valve body 31 of the embodiment.

DESCRIPTION OF SYMBOLS 1 Valve body 1A Valve chamber 1A1 Back space 1A2 Pressure equalization path 2 Valve guide 2a Guide surface 21 Valve seat part 21a Valve port 21b Seating surface 3 Valve member 31 Valve body 4 Connecting rod 5 Lid member 51 Male screw shaft 6 Stepping motor motor)
62 Magnet rotor 63 Female screw member L Axis

Claims (2)

A valve body in which a valve chamber is formed, a cylindrical valve guide disposed in the valve body, and a valve port slidably disposed in the valve guide and defined by a valve seat A valve member, an electric motor attached to the valve body, and a valve rod that holds the valve member and is connected to the electric motor. The electric motor moves the valve rod and the valve member in the axial direction. The valve member is moved to open and close the valve port, and the pressure balance between the fluid pressure in the back space with respect to the valve member in the valve chamber and the fluid pressure in the valve port is achieved by a seal member provided in the valve member. In the motorized valve
An annular coupling portion defining a primary port is formed on a side portion of the valve guide with respect to the axis, and a valve seat portion defining a valve port is formed at an open end facing the secondary port of the valve guide. The valve seat portion has a tapered seat surface facing the inside of the valve guide around the valve port, and a valve body that is slidably contacted with the valve guide of the valve member is formed on the valve guide. A cylindrical valve body that can be inserted into the guide surface of the valve guide from the side opposite to the valve seat portion and whose outer peripheral end portion can contact the seating surface, and the valve guide in the valve chamber of the valve body The valve guide is formed integrally with the valve body through the coupling portion so that the primary port is conducted to a primary joint pipe provided in the valve body. Features a motorized valve.   The motor-operated valve according to claim 1, wherein the valve guide and the valve main body are integrally formed by brazing or MIM (Metal Injection Molding) at the joint portion.

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