Electric valve

Abstract

In the present invention, an electric valve comprises: a reduction mechanism 46 that reduces the rotation of an electric motor 31 that drives a valve body 17, and a transmission mechanism 53 that converts rotary motion into linear motion and transmits the linear motion to the valve body. The transmission mechanism has a rotary lifting shaft 48 that connects a first feed screw mechanism 54 and a second feed screw mechanism 55 that have mutually different screw directions. The first feed screw mechanism transmits the rotary motion outputted from the reduction mechanism to the second feed screw mechanism via the rotary lifting shaft, and also converts the rotary motion outputted from the reduction mechanism into linear motion and transmits the linear motion to the second feed screw mechanism via the rotary lifting shaft. The second feed screw mechanism converts the rotary motion transmitted from the first feed screw mechanism via the rotary lifting shaft into linear motion and transmits the linear motion to the valve body, and also transmits the linear motion transmitted from the first feed screw mechanism to the valve body via the rotary lifting shaft.

Description

Technical Field

[0008] ,

[0001] The present invention relates to an electric valve, and particularly to a valve structure for improving the valve body lift amount of a gear-type electric valve.

Background Art

[0002] An electric valve that controls the opening degree of a valve using an electric motor such as a stepping motor has been conventionally used in a refrigeration cycle device provided with a refrigerant circuit such as an air conditioner or a refrigerating / freezing device.

[0003] Such an electric valve includes a gear-type electric valve. Generally, a gear-type electric valve includes a valve body having a valve chamber inside and flow paths (inflow path and outflow path) for allowing refrigerant to flow in and out of the valve chamber, a valve body that opens and closes or adjusts the opening degree of the flow path by moving up and down in the valve chamber, an electric motor that drives the valve body, a speed reduction mechanism that reduces the rotation of the electric motor, and a transmission mechanism that converts the reduced rotational motion into a linear motion and transmits it to the valve body.

[0004] In addition, there is the following Patent Document 1 as a document that discloses such an electric valve.

Prior Art Document

Patent Document

[0005] Patent Document 1: Japanese Patent Application Laid-Open No. 2013-130271

Summary of the Invention

[0006] By the way, it is difficult for a conventional electric valve to increase the lift amount (lifting amount) of the valve body and increase the capacity of the valve. To increase the capacity of the electric valve, it is easy to cause structural changes or enlargement of the electric motor or speed reduction mechanism that drives the valve body, resulting in an increase in manufacturing cost, and it becomes difficult to meet the recent demand for miniaturization of electric valves.

[0007] <00000,30>In addition, the above problems cannot be solved by the invention described in Patent Document 1 either.

[0008] Therefore, the objective of the present invention is to enable the electric valve to have a larger capacity (increase the valve body lift amount) without requiring structural changes or enlargement of the electric motor or reduction mechanism.

[0009] To solve the aforementioned problems and achieve the objective, the electric valve according to the first invention of this application comprises a valve body having a valve chamber inside that communicates with an inlet passage for introducing fluid and an outlet passage for introducing fluid; a valve body that moves back and forth relative to a valve seat formed in the valve chamber; an electric motor for driving the valve body; a reduction mechanism for reducing the rotation of the electric motor; and a transmission mechanism having a first lead screw mechanism and a second lead screw mechanism with screws facing opposite directions (in other words, if one is a standard screw, the other is a reverse screw) that converts the rotational motion reduced by the reduction mechanism into linear motion and transmits it to the valve body. The transmission mechanism also has a rotary lifting shaft. This rotary lifting shaft extends to connect the first lead screw mechanism and the second lead screw mechanism, has a first screw portion constituting the first lead screw mechanism at one end and a second screw portion constituting the second lead screw mechanism at the other end.

[0010] Furthermore, the first lead screw mechanism transmits the rotational motion output from the reduction mechanism to the second lead screw mechanism via a rotating lifting shaft, and also converts the rotational motion output from the reduction mechanism into linear motion and transmits this linear motion to the second lead screw mechanism via a rotating lifting shaft. The second lead screw mechanism also converts the rotational motion transmitted from the first lead screw mechanism via a rotating lifting shaft into linear motion and transmits it to the valve body, and also transmits the linear motion transmitted from the first lead screw mechanism via a rotating lifting shaft to the valve body.

[0011] In conventional electric valves, a lead screw mechanism (corresponding to the first lead screw mechanism of the first invention described above), which is generally provided at the output of the reduction gear mechanism, converts the rotational motion output from the reduction gear mechanism into linear motion and transmits it to the valve body.

[0012] In contrast, the electric valve according to the first invention (the second invention, described later, also provides the same effects as the first invention, and therefore these are collectively referred to as "the present invention") includes two lead screw mechanisms between the reduction mechanism and the valve body: a first lead screw mechanism located on the reduction mechanism side and a second lead screw mechanism located on the valve body side. Therefore, according to the electric valve of the present invention, in addition to the linear motion that was conventionally transmitted to the valve body, linear motion generated (converted) by the second lead screw mechanism is applied to the valve body, making it possible to obtain a larger valve body lift amount compared to conventional designs.

[0013] Furthermore, in the electric valve according to the present invention, the two lead screw mechanisms (first lead screw mechanism and second lead screw mechanism) are configured so that the direction of the screw in the first lead screw mechanism and the direction of the screw in the second lead screw mechanism are opposite to each other, so that the rotational motion is converted into linear motion in one direction additively rather than canceling each other out. In other words, the first screw portion formed at one end of the rotating lifting shaft and the second screw portion formed at the other end have opposite screw directions (if one is a standard screw, the other is a reverse screw). More specifically, if the first lead screw mechanism (first screw portion) is a right-hand screw (standard screw), then the second lead screw mechanism (second screw portion) is a left-hand screw (reverse screw), and if the first lead screw mechanism (first screw portion) is a left-hand screw (reverse screw), then the second lead screw mechanism (second screw portion) is a right-hand screw (standard screw).

[0014] Therefore, if we define the axial direction of the electric valve as "up" when the direction from the valve body towards the electric motor (reduction mechanism) and "down" when the direction from the electric motor (reduction mechanism) towards the valve body, then for example, when the rotor of the electric motor rotates and rotational motion in the first rotation direction is output from the reduction mechanism, the first lead screw mechanism generates linear motion upward, and the second lead screw mechanism also generates linear motion upward. These two linear motions upward are added together to obtain a larger lift amount compared to the conventional case (when only the first lead screw mechanism is provided).

[0015] Furthermore, when the rotor of the electric motor rotates in the opposite direction to the above, and the reduction mechanism outputs rotational motion in a second rotational direction opposite to the first rotational direction, the first lead screw mechanism generates downward linear motion, and the second lead screw mechanism also generates downward linear motion. The valve body descends by the sum of these two downward linear motions (the same amount as the lift during the upward movement described above).

[0016] Furthermore, in the first invention described above, the screw pitch of the second lead screw mechanism is made larger than the screw pitch of the first lead screw mechanism. This is to generate a larger linear motion (larger than the linear motion generated by the first lead screw mechanism) using the second lead screw mechanism, thereby increasing the valve body lift amount.

[0017] On the other hand, the first lead screw mechanism may have the same structure as a conventional lead screw mechanism, thus avoiding structural changes or enlargement of the motor and reduction mechanism, including the first lead screw mechanism. Therefore, according to the present invention, an electric valve with a large valve body lift amount can be constructed by using existing (conventional) motors and reduction mechanisms as they are. Furthermore, according to the present invention, as illustrated later in the embodiments, gate valves (shutdown valves) that require a relatively large valve body lift amount and flow control valves that require fine lift amount control can be manufactured using a common drive unit (motor and reduction mechanism) by appropriately adjusting (changing the settings) the screw pitch and number of threads of the second lead screw mechanism. This makes it possible to reduce the overall manufacturing cost when manufacturing various types of electric valves. Moreover, the above-mentioned effects can also be obtained similarly by the second invention described below.

[0018] The electric valve according to the second invention of the present application comprises a valve body having a valve chamber inside that communicates with an inlet passage for introducing fluid and an outlet passage for introducing fluid; a valve body that moves back and forth relative to a valve seat formed in the valve chamber; an electric motor for driving the valve body; a reduction mechanism for reducing the rotation of the electric motor; and a transmission mechanism having a first lead screw mechanism and a second lead screw mechanism with screws facing opposite directions (if one is a standard screw, the other is a reverse screw), which converts the rotational motion reduced by the reduction mechanism into linear motion and transmits it to the valve body. The transmission mechanism also has a rotary lifting shaft. This rotary lifting shaft extends to connect the first lead screw mechanism and the second lead screw mechanism, with a first screw portion constituting the first lead screw mechanism at one end and a second screw portion constituting the second lead screw mechanism at the other end.

[0019] Furthermore, the first lead screw mechanism transmits the rotational motion output from the reduction mechanism to the second lead screw mechanism via a rotating lifting shaft, and also converts the rotational motion output from the reduction mechanism into linear motion and transmits this linear motion to the second lead screw mechanism via a rotating lifting shaft. The second lead screw mechanism also converts the rotational motion transmitted from the first lead screw mechanism via a rotating lifting shaft into linear motion and transmits it to the valve body, and also transmits the linear motion transmitted from the first lead screw mechanism via a rotating lifting shaft to the valve body.

[0020] Furthermore, in this second invention, the number of threads in the second lead screw mechanism is greater than the number of threads in the first lead screw mechanism. That is, the electric valve according to this second invention replaces the configuration in the first invention, which "makes the screw pitch of the second lead screw mechanism greater than the screw pitch of the first lead screw mechanism," by having more threads in the second lead screw mechanism than the number of threads in the first lead screw mechanism. By increasing the number of threads in this way, it is possible to increase the linear motion (i.e., the amount of lift of the valve body) generated by the second lead screw mechanism.

[0021] Furthermore, both the feature according to the first invention (configuration related to the screw pitch) and the feature according to the second invention (configuration related to the number of threads) may be provided (that is, in the electric valve according to the second invention, the screw pitch of the second feed screw mechanism is made larger than the screw pitch of the first feed screw mechanism). According to such an electric valve, the valve body lift amount can be made even larger.

[0022] According to the present invention, it is possible to increase the valve body lift amount without causing structural changes or enlargement of the electric motor or the reduction mechanism, and to increase the capacity of the electric valve.

[0023] Other objects, features, and advantages of the present invention will be clarified by the following description of the embodiments of the present invention based on the drawings. Note that the present invention is not limited to the following embodiments, and it is obvious to those skilled in the art that various changes can be made within the scope described in the claims. Also, in each figure, the same reference numerals indicate the same or corresponding parts.

Brief Description of the Drawings

[0024] [Figure 1] FIG. 1 is a longitudinal sectional view showing a closed valve state of an electric valve according to a first embodiment of the present invention. [Figure 2] FIG. 2 is a longitudinal sectional view showing an open valve (fully open) state of the electric valve according to the first embodiment. [Figure 3] FIG. 3 is a perspective view showing a valve body of the electric valve according to the first embodiment. [Figure 4] FIG. 4 is a longitudinal sectional view showing a closed valve state of an electric valve according to a second embodiment of the present invention. [Figure 5] FIG. 5 is a longitudinal sectional view showing an open valve (fully open) state of the electric valve according to the second embodiment. [Figure 6] FIG. 6 is a longitudinal sectional view showing a closed valve state of an electric valve according to a third embodiment of the present invention. [Figure 7] FIG. 7 is a longitudinal sectional view showing an open valve (fully open) state of the electric valve according to the third embodiment. [Figure 8]Figure 8 is a longitudinal cross-sectional view showing the closed state of an electric valve according to the fourth embodiment of the present invention. [Figure 9] Figure 9 is a longitudinal cross-sectional view showing the open (fully open) state of the electric valve according to the fourth embodiment. [Best Mode for Carrying Out the Invention]

[0025] An electric valve according to an embodiment of the present invention will be described with reference to Figures 1 to 9. Each figure will appropriately display mutually orthogonal two-dimensional or three-dimensional coordinates representing the up / down, left / right, and front / back directions, and the following description will be based on these directions. However, the electric valves of the present invention and each embodiment can be used in various orientations, and these directions are for convenience of explanation only; the configuration of each part of the present invention is not limited in any way by these directions. Furthermore, while the terms "vertical" and "horizontal" are sometimes used, the vertical direction coincides with the up / down direction, and the horizontal direction, which is orthogonal to the vertical direction, includes the left / right and front / back directions.

[0026] [First Embodiment] The electric valve 11 according to the first embodiment of the present invention is a gate valve suitable for use in a refrigeration cycle device such as an air conditioner to open and close the flow path of a refrigerant.

[0027] As shown in Figures 1 to 3, the gate valve 11 comprises a valve body 12 having a valve chamber 13 inside, an inlet passage 15 for introducing refrigerant into the valve chamber 13, and an outlet passage 16 for releasing refrigerant from the valve chamber 13; a valve seat 14 formed in the valve chamber 13; a valve element 17 that opens and closes the refrigerant flow path by moving back and forth (up and down) relative to the valve seat 14; an electric motor 31 that drives the valve element 17; a reduction mechanism (planetary gear reduction mechanism) 46 that reduces the rotation of the electric motor 31; a transmission mechanism 53 that includes a rotating lifting shaft 48 and converts the rotational motion reduced by the reduction mechanism 46 into linear motion and transmits it to the valve element 17; a can (sealed container) 25 having a cylindrical shape with no bottom and a lid (the bottom is open and the top is closed) and forming a sealed space on the upper side of the valve body 12; and a connecting member 19 that connects the valve body 12 and the can 25. Furthermore, as will be described in detail later, the transmission mechanism 53 has two feed screw mechanisms: a first feed screw mechanism 54 provided on the reduction mechanism 53 side and a second feed screw mechanism 55 provided on the valve body 17 side.

[0028] The valve chamber 13 is formed in the lower central part of the valve body 12, and the inlet passage 15 and outlet passage 16 extend horizontally to the left and right of the valve chamber 13. Specifically, the inlet passage 15 extends horizontally from the right side of the valve body 12 to the valve chamber 13 and opens to the right inner side of the valve chamber 13 (this opening 15a of the inlet passage 15 relative to the valve chamber 13 is called the "inlet").

[0029] On the other hand, the outflow passage 16 extends horizontally from the left side of the valve body 12 to the valve chamber 13 and opens to the left inner surface of the valve chamber 13 (this opening 16a of the outflow passage 16 to the valve chamber 13 is called the "outlet"). The right inner surface of the valve chamber 13 where the inflow passage 15 opens (especially the wall surface around the inlet 15a) and the left inner surface of the valve chamber 13 where the outflow passage 16 opens (especially the wall surface around the outlet 16a) form the valve seat 14 to which the valve body 17 makes contact and separates (contacts and separates). In addition, both inner surfaces of the valve chamber 13 (left inner surface and right inner surface) are tapered slopes in which the distance between them (left inner surface and right inner surface) narrows as they extend downwards.

[0030] The valve body 17 has a block-shaped valve body portion 17a having a roughly rectangular parallelepiped shape, and a cylindrical columnar portion 17b rising vertically upward from the upper surface of the valve body portion 17a. Both sides (left side and right side) of the valve body portion 17a are tapered slopes that narrow in distance from each other downwards, corresponding to the inner sides of the valve chamber 13. When the valve is closed, the valve body 17 is inserted into the valve chamber 13 in a wedge shape, so that the left side of the valve body portion 17a is in close contact with the left inner surface of the valve chamber 13, and the right side of the valve body portion 17a is in close contact with the right inner surface of the valve chamber 13, thereby closing the inlet 15a and outlet 16a with the valve body portion 17a.

[0031] Furthermore, even in its fully open position (see Figure 2), the lower end of the valve body 17 is positioned between the two inner surfaces of the valve chamber 13 (in other words, the lower end of the valve body 17 is located below the upper ends of the two inner surfaces of the valve chamber 13 in the vertical direction). Therefore, during its raising and lowering operation, the valve body 17 is always restricted by the two inner surfaces of the valve chamber 13 (although it may rotate slightly with the rotary lifting shaft 48 when the rotary lifting shaft 48 rotates, its rotation is restricted by contact with the two inner surfaces of the valve chamber 13). This prevents the valve body 17 from rotating with the rotary lifting shaft 48 when the valve is opened, which would prevent it from fitting between the two inner surfaces of the valve chamber 13 when the valve is closed again, thus hindering the closing operation.

[0032] Furthermore, the columnar portion 17b supports the valve body 17 on the rotating lifting shaft 48 and constitutes the second feed screw mechanism 55, which will be explained later together with the transmission mechanism 53. In addition, an opening 12a (referred to as the "connection opening") is formed on the upper surface of the valve body 12, which communicates with the valve chamber 13, and a connecting member 19 is fixed to this connection opening 12a so as to close the top surface of the valve chamber 13.

[0033] The connecting member 19 has a cylindrical fitting portion 20 that fits into a connecting opening 12a formed on the upper surface of the valve body 12, and a cylindrical projection portion 21 that communicates with the fitting portion 20, rises upward from the upper surface of the fitting portion 20, and extends upward from the upper surface of the valve body 12. The connecting member 19 is fixed to the valve body 12 by first fitting the fitting portion 20 into the connecting opening 12a, and then screwing a ring-shaped retaining member 23, which has a male thread on its outer surface that screws into a female thread formed on the inner surface of the connecting opening 12a, into the connecting opening 12a.

[0034] The insertion portion 20 has a central hole 20a that penetrates vertically through its center, and this central hole 20a is equipped with two stepped portions 20b such that the diameter of the hole decreases in stages (in two stages) as it moves upward in a stepped manner. When the valve is open (fully open), the upper surface of the columnar portion 17b abuts against the upper stepped portion 20b, stopping the valve body 17.

[0035] On the other hand, the protruding portion 21 has a stepped portion on its outer circumferential surface, and the lower end of the can 25 is joined to this stepped portion, for example, by welding via a ring-shaped base member 22. This creates a sealed space that includes the internal spaces of the valve chamber 13, the connecting member 19 (fitting portion 20 and protruding portion 21), and the internal space of the can 25, all of which are in communication with each other.

[0036] Furthermore, in order to prevent refrigerant from leaking out of the sealed space through the connection opening 12a of the valve body 12, a sealing member (O-ring) 24 is provided on the outer surface of the fitting portion 20 so as to be interposed between it and the inner surface of the connection opening 12a. In addition, a sealing member (O-ring) 24a is also provided on the outer surface of the protruding portion 21 so as to be interposed between it and the inner surface of the leg portion 47a (described later) of the resin molded cover. This sealing member 24a prevents moisture and other substances from entering the electric motor 31 (resin molded cover 47) from the outside.

[0037] The electric motor 31 is a stepping motor comprising a stator 32 positioned outside the can 25, a rotor 33 rotatably positioned inside the can 25, and a resin molded cover 47 covering the can 25 and the stator 32. The resin molded cover 47 has cylindrical legs 47a at its lower end that surround the protruding portion 21 of the connecting member 19 at regular intervals.

[0038] The stator 32, located on the outside of the can 25, includes a yoke 36 and a coil 38 with windings on a bobbin 37. On the other hand, the rotor 33, located on the inside of the can 25, is constructed by integrally connecting a cylindrical rotor member 33a made of magnetic material (permanent magnet) and a sun gear member 39 made of resin material.

[0039] A rotor support shaft 34 is inserted into the center of the sun gear member 39, and the upper part of the rotor support shaft 34 is supported by a support member 35 positioned inside the top of the can 25.

[0040] The sun gear 39a of the sun gear member 39 meshes with a plurality of planetary gears 40 that are rotatably supported on a shaft 43 provided on a carrier 44 mounted on the bottom surface of the output gear 45. The upper part of the planetary gears 40 meshes with an annular ring gear (internal fixed gear) 41 attached to the top of a cylindrical gear case 56 fixed to the top of the protrusion 21 of the connecting member 19. The lower part of the planetary gears 40 meshes with an internal gear 42 of the annular output gear 45. The number of teeth of the ring gear 41 and the number of teeth of the internal gear 42 of the output gear 45 are slightly different, so that the rotational speed of the sun gear 39a is reduced by a large reduction ratio and transmitted to the output gear 45. These gear mechanisms (sun gear 39a, planetary gears 40, ring gear 41, and output gear 45) constitute a reduction mechanism (mysterious planetary gear reduction mechanism) 46 that reduces the rotation of the stepping motor 31 as described above.

[0041] In this embodiment (and the embodiments described later), a unique planetary gear reduction mechanism is employed, which provides a high reduction ratio and is advantageous for miniaturization. However, in the present invention, the reduction mechanism 46 is not limited to the unique planetary gear reduction mechanism; it may be any other planetary gear reduction mechanism, or any gear mechanism other than a planetary gear reduction mechanism.

[0042] A cylindrical screw bearing 26 is press-fitted into the protruding portion 21 of the connecting member 19. The output gear 45 is in slidable contact with the upper surface of the screw bearing 26. The upper part of a stepped cylindrical output shaft 29 is press-fitted into the center of the bottom of the output gear 45, and the lower part of the output shaft 29 is rotatably inserted into a fitting hole 27 formed in the center of the upper surface of the screw bearing 26. The lower end of the rotor support shaft 34 is also fitted to the upper part of the output shaft 29 so as to be rotatable relative to it.

[0043] A female threaded portion (referred to as the "first female threaded portion") 28 is formed at the lower center of the screw bearing 26, and a male threaded portion (referred to as the "first male threaded portion" / corresponding to the "first threaded portion" in this invention) 49 formed at the upper part of the rotary lifting shaft 48 is screwed into this first female threaded portion 28. These screw bearing 26 (first female threaded portion 28) and rotary lifting shaft 48 (first male threaded portion 49) constitute a transmission mechanism 53 (first feed screw mechanism 54) that converts the rotational motion supplied from the electric motor 31 via the reduction mechanism 46 into vertical linear motion and transmits it to the valve body 17.

[0044] The rotating lifting shaft 48 is a rod-shaped member that extends vertically in the vertical direction along the central axis A of the gate valve 11 from the center of the screw bearing 26 to the valve body 17. The rod-shaped member has a cylindrical portion located at the upper part of the rod-shaped member on which the first male thread portion 49 is formed on its outer surface (referred to as the "first cylindrical portion"), a cylindrical portion located at the lower end of the rod-shaped member on which a male thread portion (referred to as the "second male thread portion" / corresponding to the "second thread portion" in this invention) 50 is formed on its outer surface (referred to as the "second cylindrical portion"), a connecting portion 51 that connects the first cylindrical portion and the second cylindrical portion, and a flat screwdriver-shaped plate portion 52 that stands vertically upward from the upper surface of the first cylindrical portion.

[0045] Here, the output gear 45 rotates without moving up or down at a fixed position in the vertical direction, and the rotational motion of the output gear 45 is transmitted to the rotary lifting shaft 48 by inserting a flat screwdriver-shaped plate portion 52 provided at the upper end of the rotary lifting shaft 48 into a slit-shaped fitting groove 30 provided at the lower end of the output shaft 29 connected to the output gear 45. The rotary lifting shaft 48, upon receiving this rotational motion, rotates together with the output shaft 29, and at the same time, the plate portion 52 slides vertically within the fitting groove 30 of the output shaft 29, causing the first lead screw mechanism 54 to move linearly in the vertical direction. In other words, the rotary lifting shaft 48 moves linearly in the vertical direction while rotating, even though the output gear 45 (rotor 33) does not move vertically.

[0046] The linear motion of the rotary lifting shaft 48 is transmitted to the valve body 17. The valve body 17 is located at the lower end of the rotary lifting shaft 48. Specifically, the columnar portion 17b of the valve body 17 has a screw hole that penetrates its center in the vertical direction. This screw hole has an internal screw (referred to as the "second internal screw portion") 18 on its inner surface that screws into the second internal screw portion 50 formed at the lower end of the rotary lifting shaft 48.

[0047] Furthermore, following the above-mentioned screw hole (second female screw portion) 18 (so as to communicate with it), a through hole 17c is formed in the valve body portion 17a that penetrates the valve body portion 17a in the vertical direction and has a larger diameter than the screw hole 18. Therefore, in this embodiment, the valve body 17 has a hole that penetrates the entire valve body vertically, formed by these mutually communicating screw holes 18 and through hole 17c. Thus, with a valve body structure having such a hole, it is possible to easily perform the processing of forming the screw hole (second female screw portion) 18 during manufacturing, and it is possible to completely discharge and remove the chips generated during the threading process through the through hole 17c.

[0048] To install the valve body 17 on the rotating lifting shaft 48, the lower end of the rotating lifting shaft 48 is screwed into the columnar portion 17b while simultaneously screwing it into the second female threaded portion 18. This allows the valve body 17 to be supported by the lower end of the rotating lifting shaft 48. Therefore, the valve body 17 and the rotating lifting shaft 48 are able to rotate relative to each other.

[0049] However, as mentioned above, the valve body 17 is always restricted in the direction of rotation (operational limitation) by the inner surfaces of both sides of the valve chamber 13, so even if the rotary lifting shaft 48 rotates, the rotation of the valve body 17 is restricted and its posture (position in the direction of rotation) is maintained. For this reason, when the rotary lifting shaft 48 rotates in response to the rotation of the output shaft 29, the valve body 17 rotates relative to the rotary lifting shaft 48, and the feed screw action of the second male threaded portion 50 of the rotary lifting shaft 48 and the second female threaded portion 18 of the valve body 17, which are screwed together, makes it possible to move the valve body 17 in the vertical direction relative to the rotary lifting shaft 48.

[0050] Furthermore, the second female thread portion 18 of the valve body 17 and the second male thread portion 50 at the lower end of the rotary lifting shaft 48 constitute a transmission mechanism 53 (second feed screw mechanism 55) that converts the rotational motion supplied from the electric motor 31 via the reduction mechanism 46 and the rotary lifting shaft 48 into vertical linear motion and transmits it to the valve body 17.

[0051] Furthermore, in this embodiment, the central axes A of the columnar portion 17b of the valve body 17, the rotary lifting shaft 48, the screw bearing 26, the output shaft 29, and the rotor support shaft 34 coincide with the rotation axis of the rotor 33 and the axis A of the electric valve 11 that extends vertically in the vertical direction.

[0052] Furthermore, the gate valve 11 of this embodiment is equipped with the following characteristic configurations (1) to (3) for the feed screw mechanism (first feed screw mechanism 54 and second feed screw mechanism 55), which makes it possible to increase the lift amount of the valve body 17 compared to the conventional valve.

[0053] (1) The direction of the threads of the second feed screw mechanism 55 (second male thread portion 50 and second female thread portion 18 / hereinafter the same) is opposite to the direction of the threads of the first feed screw mechanism 54 (first male thread portion 49 and first female thread portion 28 / hereinafter the same). This is to allow the two feed screw mechanisms (first feed screw mechanism 54 and second feed screw mechanism 55) to convert rotational motion into linear motion in one direction additively rather than canceling each other out. For example, if the first feed screw mechanism 54 is a right-hand thread, then the second feed screw mechanism 55 is a left-hand thread. Also, if the first feed screw mechanism 54 is a left-hand thread, then the second feed screw mechanism 55 is a right-hand thread.

[0054] (2) The screw pitch of the second lead screw mechanism 55 is greater than the screw pitch of the first lead screw mechanism 54.

[0055] (3) The number of threads in the second lead screw mechanism 55 is greater than the number of threads in the first lead screw mechanism 54.

[0056] The operation of the gate valve 11 according to this embodiment is as follows.

[0057] When current is supplied to the stator 32 (coil 38) so that the rotor 33 rotates in one direction from the closed valve state shown in Figure 1, the rotation of the rotor 33 is converted into linear motion by the first lead screw mechanism 54, and the rotary lifting shaft 48 is pulled upward together with the valve body 17. At the same time, the rotation of the rotor 33 is transmitted to the second lead screw mechanism 55 via the rotary lifting shaft 48, and this rotation is also converted into linear motion in the second lead screw mechanism 55, causing the valve body 17 to be pulled upward relative to the rotary lifting shaft 48. In particular, the second lead screw mechanism 55 has a large lift amount for the valve body 17 due to the characteristic configurations (2) and (3) regarding the screw pitch and number of threads, and together with the upward linear motion generated by the first lead screw mechanism 54, the valve body 17 is pulled upward significantly. As a result, the valve body portion 17a separates from the valve seat 14, and the refrigerant that flowed in from the inlet passage 15 flows out from the outlet passage 16 through the valve chamber 13 (see arrow F in Figure 2).

[0058] On the other hand, when current is supplied to the stator 32 (coil 38) so that the rotor 33 rotates in the opposite direction to the above-mentioned unidirectional state from this open (fully open) state, the rotation of the rotor 33 is converted into linear motion by the first lead screw mechanism 54 and the second lead screw mechanism 55, and the rotational lifting shaft 48 moves downward together with the valve body 17, and the valve body 17 moves downward relative to the rotational lifting shaft 48. Then, when the valve body portion 17a comes into contact with the valve seat 14, the flow path between the inlet passage 15 and the outlet passage 16 is blocked, resulting in a closed valve state (see Figure 1).

[0059] [Second Embodiment] The electric valve 61 according to the second embodiment of the present invention will be described with reference to Figures 4 and 5. Components identical or equivalent to those in the electric valve 11 of the first embodiment are denoted by the same reference numerals, and redundant explanations are omitted, with the focus being on the differences (the same applies to the third and fourth embodiments described later).

[0060] As shown in Figures 4 and 5, the electric valve 61 according to the second embodiment of the present invention is a gate valve that, like the electric valve 11 of the first embodiment, comprises a valve body 12 having a valve chamber 13, a valve seat 14, an inlet passage 15 and an outlet passage 16, a valve element 17 that opens and closes the refrigerant flow path by moving back and forth relative to the valve seat 14, an electric motor 31 that drives the valve element 17, a reduction mechanism (planetary gear reduction mechanism) 46 that reduces the rotation of the electric motor 31, a transmission mechanism 53 (first lead screw mechanism 54 and second lead screw mechanism 55) that converts the rotational motion reduced by the reduction mechanism 46 into linear motion and transmits it to the valve element 17, a can (sealed container) 25 that forms a sealed space on the upper surface of the valve body 12, and a connecting member 19 that connects the valve body 12 and the can 25, but the structure of the valve element 17 differs from that of the first embodiment.

[0061] Specifically, the valve body 17 comprises a block-shaped valve body main portion 17a and a columnar portion 17b, similar to the first embodiment. However, while the first embodiment had holes 18 and 17c that penetrated the entire valve body vertically, this embodiment does not have a through hole 17c in the valve body main portion 17a. Instead, a screw hole 18 forming the second female screw portion is formed to extend from the upper surface of the columnar portion 17b to near the lower surface of the valve body main portion 17a (so as not to reach the lower surface of the valve body main portion 17a and penetrate the valve body 17).

[0062] In this embodiment, as in the first embodiment, the upper surface of the columnar portion 17b abuts against the upper stepped portion 20b of the connecting member 19 when the valve is open (fully open), stopping the valve body 17. On the other hand, in this abutting state when the valve is open, the central hole 20a of the connecting member 19 (fitting portion 20) is closed by the columnar portion 17b of the valve body 17, blocking communication between the valve chamber 13 and the inside of the can 25. This valve body structure of this embodiment has the following advantages.

[0063] Foreign matter such as dust and metal fragments may be mixed into the refrigerant, and such foreign matter can interfere with the normal operation of the electric motor 31, the reduction mechanism 46, and the transmission mechanism 53 (first feed screw mechanism 54). In contrast, according to this embodiment, communication between the valve chamber 13 and the inside of the can 25 can be blocked when the valve is opened, so that malfunctions caused by foreign matter in the refrigerant can be prevented.

[0064] The operation of the gate valve 61 according to this embodiment is the same as that of the gate valve 11 in the first embodiment.

[0065] [Third Embodiment] A third embodiment of the electric valve of the present invention will be described with reference to Figures 6 and 7.

[0066] The electric valve 71 of this embodiment is a flow control valve suitable for use in refrigeration cycle devices such as air conditioners to control the flow rate of refrigerant.

[0067] As shown in Figures 6 and 7, the flow control valve 71 comprises a valve body 12 having a valve chamber 13, an inlet passage 15, and an outlet passage 16; a valve opening (orifice) 72 formed between the inlet passage 15 and the valve chamber 13; a valve seat 14 formed at the valve chamber side end of the valve opening 72; a valve element 17 that controls the flow rate of refrigerant by moving back and forth relative to the valve seat 14; an electric motor 31 that drives the valve element 17; a reduction mechanism (planetary gear reduction mechanism) 46 that reduces the rotation of the electric motor 31; a transmission mechanism 53 that converts the rotational motion reduced by the reduction mechanism 46 into linear motion and transmits it to the valve element; a can (sealed container) 25 that forms a sealed space on the upper surface of the valve body 12; and a connecting member 73 that connects the valve body 12 and the can 25.

[0068] The transmission mechanism 46 is the same as in the second embodiment in that it includes a rotary lifting shaft 48 and consists of a first feed screw mechanism 54 (consisting of a first male threaded portion 49 formed on the upper part of the rotary lifting shaft 48 and a first female threaded portion 28 formed on the screw bearing 26) and a second feed screw mechanism 55 (consisting of a second male threaded portion 50 formed on the lower end of the rotary lifting shaft 48 and a second female threaded portion 18 formed on the valve body 17), with the screw directions being opposite to each other.

[0069] The valve body 17, as in the second embodiment, has a valve body main portion 17a that moves toward and away from the valve seat 14, and a cylindrical columnar portion 17b that rises vertically upward from the upper surface of the valve body main portion 17a. However, in this embodiment, since the valve opening 72 has a circular horizontal cross-sectional shape and the valve seat 14 has a ring-shaped planar shape, the valve body main portion 17a has a disc shape (circular horizontal cross-sectional shape) to correspond to these (so that it can seat on the valve seat 14 and close the valve opening 72). Also, the screw hole forming the second female screw portion 18 is formed, as in the second embodiment, to extend from the upper surface of the columnar portion 17b to near the lower surface of the valve body main portion 17a (so that it does not reach the lower surface of the valve body main portion 17a and penetrate the valve body 17).

[0070] Furthermore, in this embodiment, the connecting member 73 is provided with a function to guide the valve body 17. Specifically, unlike the embodiments described above, in this embodiment, the central hole 20a of the fitting portion 20 is straight (straight without a stepped portion 20b), and the columnar portion 17b of the valve body 17 is fitted into this central hole 20a so as to be able to slide up and down. The valve body 17 moves up and down while being guided by the central hole 20a into which the columnar portion 17b is fitted.

[0071] In this embodiment, the connecting member 73 has a male thread on its outer surface that screws into a female thread formed in the connecting opening 12a of the valve body 12, and is fixed to the valve body 12 by screwing it into the connecting opening 12a without using a retaining member 23 as used in the first and second embodiments (the same applies to the connecting member 82 of the fourth embodiment which will be described later).

[0072] Furthermore, the outer circumference of the columnar portion 17b of the valve body 17 has a cylindrical shape with a horizontal cross-section of D (or a square, etc.), and the central hole 20a of the fitting portion 20 also has a horizontal cross-section of D (or a square, etc.), and the planar portions of these holes become sliding surfaces, preventing the valve body 17 from rotating around its axis A. The electric valve 81 of the fourth embodiment, which will be described later, also has a similar structure to prevent the valve body 17 from rotating around its axis A.

[0073] The operation of the flow control valve 71 according to this embodiment is as follows.

[0074] When current is supplied to the stator 32 (coil 38) so that the rotor 33 rotates in one direction from the closed valve state shown in Figure 6, the rotation of the rotor 33 is converted into linear motion by the first lead screw mechanism 54, and the rotary lifting shaft 48 is pulled upward together with the valve body 17. At the same time, the rotation of the rotor 33 is transmitted to the second lead screw mechanism 55 via the rotary lifting shaft 48, and this rotation is also converted into linear motion in the second lead screw mechanism 55, causing the valve body 17 to be pulled upward relative to the rotary lifting shaft 48. The amount of lift (upward movement) of the valve body 17 is the sum of the amount of lift generated by the first lead screw mechanism 54 and the amount of lift generated by the second lead screw mechanism 55, which causes the valve body 17a to separate from the valve seat 14, resulting in an open valve state where the refrigerant flowing in from the inlet passage 15 flows out from the outlet passage 16 through the valve port 72 and valve chamber 13 (see arrow F in Figure 7). Furthermore, the amount of refrigerant passing through (refrigerant flow rate) in this open valve state can be adjusted by the amount of rotation of the rotor 33.

[0075] On the other hand, when current is supplied to the stator 32 (coil 38) so that the rotor 33 rotates in the opposite direction to the above-mentioned unidirectional rotation from this open valve state, the rotation of the rotor 33 is converted into linear motion by the first lead screw mechanism 54 and the second lead screw mechanism 55, causing the rotational lifting shaft 48 to move downward together with the valve body 17, and the valve body 17 to move downward relative to the rotational lifting shaft 48. Then, when the valve body portion 17a comes into contact with the valve seat 14, the flow path between the inlet passage 15 and the outlet passage 16 is blocked, resulting in a closed valve state (see Figure 6).

[0076] [Fourth Embodiment] A fourth embodiment of the electric valve of the present invention will be described with reference to Figures 8 and 9.

[0077] As shown in Figures 8 and 9, the electric valve 81 of this embodiment is a flow control valve that controls the flow rate of refrigerant by comprising an electric motor 31, a reduction mechanism 46, and a transmission mechanism 53 (first lead screw mechanism 54 and second lead screw mechanism 55), similar to the third embodiment. However, it improves the valve opening performance by incorporating a structure that cancels the differential pressure between the upper and lower parts of the valve body.

[0078] Specifically, in this embodiment, a cylindrical valve body guide portion 83 is formed in the fitting portion 20 of the connecting member 82, and the valve body 17 is slidably housed in this valve body guide portion 83. The valve body 17 has a valve body main portion 17a that moves toward and away from the valve seat 14, and a columnar portion 17b that rises upward from the upper surface of the valve body main portion 17a. When the valve body main portion 17a is lowered, it protrudes from the lower internal space of the valve body guide portion 83 through the lower opening of the valve body guide portion 83 toward the valve seat 14, and when it is raised, it retracts into the lower inner space of the valve body guide portion 83 through the same lower opening. Even when the amount of protrusion of the valve body main portion 17a from the valve body guide portion 83 is at its maximum (i.e., when the valve is closed), the upper end of the valve body main portion 17a where the sealing member 86 (described later) is located is positioned within the lower inner space of the valve body guide portion 83.

[0079] A back pressure chamber 84 is formed on the upper side of the valve body 17a, more specifically, within the internal space of the valve body guide portion 83 and on the upper surface side of the valve body 17a (around the lower part of the columnar portion 17b). A pressure equalization passage 85 is formed in the valve body 17, connecting the central lower surface of the valve body 17a (the part facing the valve opening 72 when the valve is closed) to the back pressure chamber 84, thereby introducing the low pressure from the inlet passage 15 into the back pressure chamber 84. The pressure equalization passage 85 consists of a vertical passage 85a extending upward from the central lower surface of the valve body 17a through the interior of the valve body 17 to the lower part of the columnar portion 17b, and a horizontal passage 85b that communicates with the vertical passage 85a, extends horizontally at the lower part of the columnar portion 17b, and opens into the back pressure chamber 84. The second female thread portion 18 is formed on the upper part of the columnar portion 17b (above the horizontal passage 85b).

[0080] Furthermore, a sealing member 86 is provided on the upper outer peripheral surface of the valve body portion 17a so as to be interposed between it and the inner peripheral surface of the valve body guide portion 83 in order to prevent the outflow passage 16 and the back pressure chamber 84 from communicating when the valve is closed. This sealing member 86 consists of an O-ring 87 and a lip seal 88 with low sliding resistance that is positioned outside the O-ring 87 and slides into contact with the inner peripheral surface of the valve body guide portion 83.

[0081] Furthermore, in this embodiment, the cross-sectional area inside the outer circumference of the columnar portion 17b and the valve body portion 17a is set to be approximately the same as the cross-sectional area of ​​the valve opening 72. Therefore, in the closed valve state (Figure 8), the downward force (force in the valve closing direction) and the upward force (force in the valve opening direction) acting on the valve body 17 are balanced, making it possible to more reliably raise the valve body 17 in the closed state and perform the valve opening operation.

[0082] The operation of the flow control valve 81 according to this embodiment is the same as that of the flow control valve 71 according to the third embodiment. However, when the valve body 17 is raised from the closed state (Figure 8) to open (Figure 9), the differential pressure cancellation structure (back pressure chamber 84 and equalizing passage 85) balances the force pushing down and the force pushing up the valve body 17 as described above. Therefore, compared to the flow control valve 71 of the third embodiment, the valve body 17 can be raised more reliably to perform the opening operation. Accordingly, this embodiment is particularly advantageous when the differential pressure on the valve body increases due to the increased capacity of the electric valve. [Explanation of Symbols]

[0083] A axis (center axis) F Refrigerant flow 11.61 Electric valve (gate valve) 71,81 Electric valve (flow control valve) 12 Valve body 12a Connection opening 13 valve chambers 14 valve seats 15 Inflow channel 15a Inlet 16 Outflow channel 16a Outlet 17 Valve body 17a Valve body 17b Column 17c through hole 18. Second female thread section (thread hole) 19,73,82 Connecting members 20 Inset part 20a center hole 20b Stepped section 21 Protrusion 22 Base member 23 Retaining member 24,24a Sealing member 25 Cans (sealable containers) 26 Screw bearings 27 Insertion holes 28 First female thread section 29 Output shaft 30 Fitting groove 31. Electric motor (stepping motor) 32 stata 33 Rotors 33a Rotor component 34 Rotor support shaft 35 Support member 36 York 37 bobbins 38 coils 39. Solar gear component 39a Sun Gear 40 Planetary Gears 41 Ring gear (internal gear with fixed teeth) 42 Internal gear 43 shafts 44 carriers 45 Output Gear 46. ​​Reduction Mechanism (Mysterious Planetary Gear Reduction Mechanism) 47 Resin molded cover 47a Legs of resin molded cover 48 Rotating Lifting Axis 49 First male thread section 50 Second male thread section 51 Liaison Department 52 Plate-like part 53 Transmission Mechanism 54. First feed screw mechanism 55. Second feed screw mechanism 56 Gear Case 72. Valve orifice 83 Valve body guide section 84 Back pressure chamber 85 Pressure Equalizing Path 85a vertical path 85b horizontal path 86 Sealing member 87 O-rings 88 Lip Seals

Claims

1. A valve body having a valve chamber inside that communicates with an inlet passage for introducing fluid and an outlet passage for releasing the fluid, A valve body that moves back and forth relative to a valve seat formed in the valve chamber, The electric motor that drives the valve body, A reduction mechanism for reducing the rotation of the aforementioned electric motor, A transmission mechanism having a first feed screw mechanism and a second feed screw mechanism with screws facing opposite directions, which converts the rotational motion reduced by the reduction mechanism into linear motion and transmits it to the valve body, Equipped with, The transmission mechanism has a rotary lifting shaft that extends to connect the first lead screw mechanism and the second lead screw mechanism, has a first threaded portion constituting the first lead screw mechanism at one end and a second threaded portion constituting the second lead screw mechanism at the other end, The screw pitch of the second lead screw mechanism is greater than the screw pitch of the first lead screw mechanism. The first lead screw mechanism transmits the rotational motion output from the reduction mechanism to the second lead screw mechanism via the rotary lifting shaft, and converts the rotational motion output from the reduction mechanism into linear motion and transmits the linear motion to the second lead screw mechanism via the rotary lifting shaft. The second lead screw mechanism converts the rotational motion transmitted from the first lead screw mechanism via the rotary lifting shaft into linear motion and transmits it to the valve body, and also transmits the linear motion transmitted from the first lead screw mechanism via the rotary lifting shaft to the valve body. The valve body is prevented from rotating together with the rotating lifting shaft by contacting both inner surfaces of the valve chamber during the lifting operation. An electric valve characterized by the following features.

2. (delete)

3. A valve body having a valve chamber inside that communicates with an inlet passage for introducing fluid and an outlet passage for releasing the fluid, A valve body that moves back and forth relative to a valve seat formed in the valve chamber, The electric motor that drives the valve body, A reduction mechanism for reducing the rotation of the aforementioned electric motor, A transmission mechanism having a first feed screw mechanism and a second feed screw mechanism with screws facing opposite directions, which converts the rotational motion reduced by the reduction mechanism into linear motion and transmits it to the valve body, Equipped with, The transmission mechanism has a rotary lifting shaft that extends to connect the first lead screw mechanism and the second lead screw mechanism, has a first threaded portion constituting the first lead screw mechanism at one end and a second threaded portion constituting the second lead screw mechanism at the other end, The number of threads in the second lead screw mechanism is greater than the number of threads in the first lead screw mechanism. The first lead screw mechanism transmits the rotational motion output from the reduction mechanism to the second lead screw mechanism via the rotary lifting shaft, and converts the rotational motion output from the reduction mechanism into linear motion and transmits the linear motion to the second lead screw mechanism via the rotary lifting shaft. The second lead screw mechanism converts the rotational motion transmitted from the first lead screw mechanism via the rotary lifting shaft into linear motion and transmits it to the valve body, and also transmits the linear motion transmitted from the first lead screw mechanism via the rotary lifting shaft to the valve body. The valve body is prevented from rotating together with the rotating lifting shaft by contacting both inner surfaces of the valve chamber during the lifting operation. An electric valve characterized by the following features.

4. (delete)

5. The screw pitch of the second lead screw mechanism is greater than the screw pitch of the first lead screw mechanism. The electric valve according to claim 3.

6. The system further comprises a can that rotatably houses the rotor included in the electric motor and a connecting member that connects the can to the valve body, When the valve body is in its highest, fully open position, the valve body comes into contact with the connecting member, thereby stopping the valve body from rising. The electric valve according to claim 1, 3, or 5.

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