Electric valve

Abstract

To achieve further improvement of assemblability of a gear type electric valve and enables a test of a whole gear device to achieve further improvement of reliability of the electric valve.SOLUTION: An electric valve 11 includes: a valve body 12 having a valve chamber 13; a first flow passage 14 communicating with the valve chamber; a second flow passage 15 communicating with the valve chamber; an orifice 16 provided between the first flow passage and the second flow passage; a valve body 18 configured to move forward / backward relative to the orifice and thereby change an opening of the orifice; a rotor 24 constituting an electric motor 51 for driving the valve body; a gear device 22 configured to decelerate rotation of the rotor; an output shaft 36 configured to output rotation decelerated by the gear device; a transmission mechanism 43 configured to convert rotation of the output shaft into linear motion to transmit the linear motion to the valve body; a cylindrical gear case 23 housing the gear device; and a guide part 37 rotatably supporting the output shaft. The output shaft, the guide part, and the gear device are supported by the gear case.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an electric valve, and more particularly to the structure of a gear portion that reduces the rotation speed of an electric motor. [Background technology]

[0002] Electric valves that use an electric motor such as a stepping motor to control the valve opening have traditionally been used in refrigeration cycle devices equipped with refrigerant circuits, such as air conditioners, refrigeration devices, and freezing devices. One such electric valve is a gear-type electric valve that is equipped with a gear device that reduces the rotation speed of the electric motor.

[0003] Such an electric valve comprises an electric motor that drives the valve element, a gear device that reduces the rotation of the electric motor, an output shaft that outputs the rotation reduced by the gear device, and a transmission mechanism that converts the rotation of the output shaft into linear motion and transmits it to the valve element, and controls the flow rate of the fluid by moving the valve element back and forth relative to an orifice formed in the flow path.

[0004] Moreover, the following Patent Document 1 is a document disclosing an invention related to such a gear type motor-operated valve. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2009-228889 A Summary of the Invention [Problem to be solved by the invention]

[0006] Incidentally, although the invention described in the above Patent Document 1 improves the assembly ease of the motor-operated valve and increases the reliability of the motor-operated valve by enabling rotation testing and evaluation, there is still room for further improvement in these respects.

[0007] Specifically, in the invention described in Patent Document 1, a gear assembly (gear module) in which the gears that make up the gear device are unitized is produced in advance, and this is then assembled into the electric valve, thereby improving assembly during manufacturing.

[0008] However, this gear assembly does not include all of the gears that make up the gear device, and an additional gear (sun gear) must be installed during manufacturing.

[0009] Also, in terms of improving reliability, the motor-operated valve described in Patent Document 1 does not have all the gears of the gear device as described above, and although it has an output shaft that outputs rotation reduced by the gear device, this output shaft is not supported by a guide portion. Therefore, in the gear assembly state, it is not possible to perform tests such as checking the operation of the gear device as a whole or measuring and confirming the reduction ratio.

[0010] Therefore, an object of the present invention is to further improve the assembly ease of a gear type motor-operated valve and to enable testing of the gear device as a whole, thereby further increasing the reliability of the motor-operated valve. [Means for solving the problem]

[0011] In order to solve the above problems and achieve the object, the electric valve of the present invention comprises a valve body having a valve chamber therein, a first flow path communicating with the valve chamber, a second flow path communicating with the valve chamber, an orifice formed between the first flow path and the second flow path, a valve body that moves toward and away from the orifice to change the opening degree of the orifice, a rotor that constitutes an electric motor that drives the valve body, a gear device that reduces the rotation of the rotor, an output shaft that outputs the rotation reduced by the gear device, a transmission mechanism that converts the rotation of the output shaft into linear motion and transmits it to the valve body, a cylindrical gear case that houses the gear device, and a guide portion that rotatably supports the output shaft, and the output shaft, the guide portion, and the gear device are supported by the gear case.

[0012] In conventional gear-type motor-operated valves, including the motor-operated valve according to the invention described in the above-mentioned Patent Document 1, the gear assembly is provided with an output shaft that outputs rotation reduced by the gear device, but the guide part that supports the output shaft is provided on the transmission mechanism side. Specifically, the transmission mechanism is made up of a feed screw (screw mechanism) that is made up of a male screw member (screw shaft / referred to as a "screw drive member" in this application) that is connected to the output shaft so as to be movable in the axial direction, and a bearing (referred to as a "bearing member" in this application) that has a female screw part that screws with the male screw member, and the output shaft is supported by rotatably fitting the output shaft into the upper part of the bearing. For this reason, in conventional motor-operated valves, it is not possible to perform inspections such as checking the operation or measuring the reduction ratio with the gear device alone (without combining it with the transmission mechanism / the same meaning below).

[0013] In contrast, in the motor-operated valve according to the present invention, the guide portion of the output shaft is not provided on the bearing as in the conventional case, but is supported on the gear case separately from the transmission mechanism (bearing). This makes it possible to perform various test inspections such as operation tests on the gear device alone, further improving the reliability of the motor-operated valve. In addition, by providing the gear device (all necessary gears) inside the gear case, the assembly of the motor-operated valve can be improved compared to the conventional case.

[0014] Furthermore, in the past, the bearings of the transmission mechanism were generally made of metal to ensure durability, and the guide portion of the output shaft integrated with the bearings had to be made of metal as well. In contrast, according to the present invention, the guide portion of the output shaft is provided separately from the transmission mechanism (bearing member), so that the bearing member is made of metal to ensure durability, while the guide portion can be formed of, for example, a slidable resin (resin with high slidability), which makes it possible to reduce the sliding resistance of the guide portion. In addition, if a slidable resin is used, the support portion of the output shaft can be made to have a greaseless structure. The guide portion can be provided in the gear case by, for example, insert molding.

[0015] In a typical embodiment of the present invention, the gear device, gear case, output shaft, guide unit, and rotor are unitized as a gear device assembly. Note that "unitization" means configuring a plurality of parts as a single coherent unit (assembly of parts) that can be incorporated into an electric valve. Furthermore, the gear device assembly may include a central shaft that rotatably supports the rotor and a support member that supports the central shaft within the can, as in the embodiment described below.

[0016] The above gear device can be configured with a paradox planetary gear mechanism as in the embodiment described later. However, the gear device referred to in the present invention is not limited to the paradox planetary gear mechanism, and the gear device referred to in the present invention can also be configured with other planetary gear mechanisms or gear mechanisms other than the planetary gear mechanism.

[0017] In the motor-operated valve according to the present invention, it is preferable that one of the inner peripheral surface of the gear case and the outer peripheral surface of the guide portion is provided with an engagement recess, and the other of the inner peripheral surface of the gear case and the outer peripheral surface of the guide portion is provided with an engagement protrusion that fits into the engagement recess to prevent rotation of the guide portion. This is to prevent the guide portion from falling off the gear case and from rotating together with the output shaft. In other words, the engagement recess and the engagement protrusion work together to prevent the guide portion from moving (displacing) in the axial direction of the gear case and from rotating.

[0018] The "engagement recess" is a portion that is recessed into the mating part (the guide part when provided on the gear case side, or the gear case when provided on the guide part side) (in other words, as viewed from the mating part). On the other hand, the "engagement protrusion" is a portion that protrudes into the mating part (the guide part when provided on the gear case side, or the gear case when provided on the guide part side) (in other words, as viewed from the mating part).

[0019] Furthermore, according to the present invention, which includes a guide section separate from the transmission mechanism (bearing member), a space can be provided between the gear device (gear case and output shaft) and the transmission mechanism. Therefore, in a preferred embodiment of the motor-operated valve of the present invention, the space is utilized to include a rotation detection means for detecting the rotation of the screw drive member.

[0020] Specifically, in the electric valve of this embodiment, the transmission mechanism includes a screw drive member that rotates in response to rotation of the output shaft and is movable back and forth relative to the output shaft, and has a male threaded portion on its outer peripheral surface, and a bearing member that has a female threaded portion that screws into the male threaded portion of the screw drive member.The electric valve further includes a driving permanent magnet that is housed in the lower part of the gear case and fixed to the screw drive member to rotate together with the screw drive member, a driven permanent magnet that is coupled to the driving permanent magnet by a magnetic coupling and is arranged on the outside of the lower outer peripheral surface of the gear case so that rotational force is transmitted from the driving permanent magnet, and a magnetic sensor that detects rotation of the driven permanent magnet.

[0021] The screw drive member constituting the transmission mechanism is connected to the output shaft so as to be slidable in the axial direction in order to function as a feed screw (the function of converting the rotation received from the output shaft into linear motion). For this reason, a certain gap (a gap for allowing relative movement) is required between the output shaft and the screw drive member. Therefore, in order to detect a more accurate position (axial displacement) of the valve body, it is preferable to detect the rotation of the screw drive member rather than the rotation of the rotor or the output shaft. However, in the conventional valve structure, as described above, the guide portion supporting the output shaft is provided on the transmission mechanism (bearing) side, so that it is difficult to detect the rotation of the screw drive member arranged inside the bearing in terms of space. In contrast, according to the above-mentioned aspect of the present invention, it is possible to detect the displacement of the valve body (valve opening) more accurately by detecting the rotation of the screw drive member. Effect of the Invention

[0022] According to the present invention, it is possible to further improve the ease of assembly and reliability of the gear type motor-operated valve.

[0023] Other objects, features, and advantages of the present invention will become apparent from 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 modifications can be made within the scope of the claims. In addition, the same reference numerals in each drawing indicate the same or corresponding parts. [Brief description of the drawings]

[0024] [Figure 1] FIG. 1 is a vertical sectional view showing a motor-operated valve (closed state) according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is an enlarged vertical cross-sectional view showing a gear device assembly of the motor-operated valve according to the first embodiment. [Diagram 3] FIG. 3 is a cross-sectional view of a lower portion of the gear device assembly (a cross-section taken along the line BB in FIG. 2). [Figure 4] FIG. 4 is a vertical sectional view showing the motor-operated valve (in an open state) according to the first embodiment. [Diagram 5] FIG. 5 is a vertical sectional view showing a motor-operated valve (closed state) according to a second embodiment of the present invention. [Figure 6] FIG. 6 is an enlarged view of a rotation detection section (part C in FIG. 5) of the motor-operated valve according to the second embodiment. [Figure 7] FIG. 7 is a plan view (view from above) showing a rotation detection section (drive permanent magnet, driven permanent magnet, and magnetic sensor) of the motor-operated valve according to the second embodiment. [Figure 8] FIG. 8 is a vertical sectional view showing the motor-operated valve (in an open state) according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0025] [First embodiment] A motor-operated valve according to a first embodiment of the present invention will be described with reference to Figures 1 to 4. In each figure, mutually orthogonal two-dimensional coordinate axes representing up, down, left, and right are appropriately displayed, and the following description will be based on these directions. However, the motor-operated valve of the present invention and this embodiment (similarly to the second embodiment described below) can be used in various orientations, and each direction is for the convenience of explanation, and the configuration of each part of the present invention is not limited by these directions in any way.

[0026] As shown in FIGS. 1 to 4 , the motor-operated valve 11 according to this embodiment is an motor-operated valve suitable for use in adjusting the flow rate of a refrigerant in a refrigeration cycle device such as a heat pump type heating and cooling system, and includes a valve body 12 having a valve chamber 13 therein and an inflow passage (first flow passage) 14 for introducing a refrigerant into the valve chamber 13 and an outflow passage (second flow passage) 15 for discharging the refrigerant from the valve chamber 13, an orifice (valve port) 16 formed between the inflow passage 14 and the valve chamber 13 (the opening of the inflow passage 14 to the valve chamber 13), a valve element 18 that changes the opening degree of the orifice 16 by moving forward and backward (moving up and down) relative to the orifice 16, and a valve element 18 that is provided to close the upper surface of the valve chamber 13 and supports the valve element 18 so as to be slidable up and down. The valve body 12 is provided with a support member 19, an electric motor 51 that drives the valve body 18, a gear device 22 that reduces the speed of the rotation generated by the electric motor 51, an output shaft 36 that outputs the rotation reduced by the gear device 22, an output shaft guide member (hereinafter simply referred to as the "guide member") 37 that supports the output shaft 36 so that it can rotate and slide, a transmission mechanism 43 that converts the rotation of the output shaft 37 into linear motion by a feed screw mechanism and transmits it to the valve body 18, a cylindrical gear case 23 that houses the gear device 22, a connecting member 40 that connects the electric motor 51 and the valve body 12, and a can (sealed container) 42 that has a cylindrical shape with no bottom and a lid (the bottom is open and the top is closed) and which, together with the connecting member 40, forms a sealed space on the upper surface of the valve body 12.

[0027] A valve seat 17 is formed at the valve chest side end of the orifice 16, against which a valve body 18 comes into contact (abuts and separates). The inside of the inflow passage 14 is provided with a mesh-like strainer 20 that allows the refrigerant to pass through but can capture foreign matter.

[0028] The electric motor 51 is a stepping motor including a stator 52 arranged outside the can 42 and a rotor (magnet rotor) 24 arranged rotatably inside the can 42.

[0029] The stator 52 disposed outside the can 42 includes a yoke (stator yoke) 53, a coil 55 wound around a bobbin 54, and a resin molded cover 56. The rotor 24 disposed inside the can 42 is configured by integrally connecting a cylindrical rotor member 25 made of a magnetic material (permanent magnet) and a sun gear member 26 made of a resin material.

[0030] A central shaft 27 is inserted into the center of the sun gear member 26 , and the upper part of the central shaft 27 is supported by a support member 28 arranged on the inside top part of the can 42 .

[0031] The sun gear 29 of the sun gear member 26 meshes with a plurality of planetary gears 33 rotatably supported on a shaft 32 provided on a carrier 31 placed on the bottom surface of the output gear 30. The upper part of the planetary gear 33 meshes with an annular ring gear (internal tooth fixed gear) 34 attached to the upper part of the gear case 23 fixed to the upper part of the connection member 40, and the lower part of the planetary gear 33 meshes with an internal tooth gear 35 of the annular output gear 30. The number of teeth of the ring gear 34 and the number of teeth of the internal tooth gear 35 of the output gear 30 are slightly different, so that the rotation speed of the sun gear 29 is reduced at a large reduction ratio and transmitted to the output gear 30. Note that these gear mechanisms (sun gear 29, planetary gears 33, ring gear 34 and output gear 30) form a paradox planetary gear reduction mechanism and constitute the gear device 22 that reduces the rotation speed of the electric motor 51 described above.

[0032] The upper part of a stepped cylindrical output shaft 36 is press-fitted into the center of the bottom of the output gear 30 to connect the output gear 30 and the output shaft 36 .

[0033] On the other hand, the inner bottom of the gear case 23 is provided with a guide member (guide portion in the present invention) 37 that supports the output shaft 36. This guide member 37 has a through hole 37a in the center, and the lower part of the output shaft 36 is held in this through hole 37a so as to be slidable and rotatable. The output gear 30 is in slidable contact with the upper surface of the guide member 37. In order to reduce the sliding resistance of the output gear 30 and the output shaft 36, the guide member 37 is formed of a sliding resin (for example, PTFE / Polytetrafluoroethylene). In addition, the lower end of the center shaft 27 is fitted into the upper part of the output shaft 36 so as not to hinder the rotation of the output shaft 36.

[0034] Further, in order to prevent the guide member 37 from falling off the gear case 23 and to prevent the guide member 37 from rotating with the rotation of the output shaft 36, a fitting structure is formed between the gear case 23 and the guide member 37. Specifically, the fitting structure is formed by forming a convex portion (engagement convex portion) 38 protruding toward the center of the gear case 23 on the gear case 23 by recessing the peripheral wall of the gear case 23 inward, and forming a concave portion (engagement concave portion) 39 into which the convex portion 38 fits on the outer circumferential surface of the guide member 37 (see Figs. 2 and 3). Note that, in this embodiment, a total of two fitting structures (pairs of convex portion 38 and concave portion 39) are provided, one pair each at diametrically opposed positions, but the number of fitting structures may be one pair or three or more pairs.

[0035] Also, the guide member 37 may be fixed to the gear case 23 by insert molding. In insert molding, a resin material that is the base of the guide member 37 is introduced into a mold in which the metal gear case 23 is placed, and then molded. For this reason, a convex portion may be formed on one of the gear case 23 and the guide member 37, and a concave portion may be formed on the other of the gear case 23 and the guide member 37. Also, a concave portion or a through hole may be provided in the gear case 23, and the guide member 37 may be insert molded, in which case a part of the guide member 37 fits into the concave portion or the through hole and is fixed.

[0036] Furthermore, in manufacturing the motor-operated valve 11 according to this embodiment (the same applies to the second embodiment described later), the gear device 22, the gear case 23, the output shaft 36, the guide member 37, the rotor 24, the center shaft 27, and the support member 28 are unitized as a gear device assembly 21. FIG. 2 shows an enlarged view of this unitized gear device assembly (also referred to as an "assembly" in the present application) 21, and by manufacturing such a unitized assembly 21, the productivity of the motor-operated valve 11 can be improved. For example, if multiple types of assemblies 21 with different gear ratios are manufactured and prepared, it is possible to immediately respond to specification changes corresponding to the load on the valve body side by selecting from these. In addition, the assembly 21 can be assembled to multiple types of valve bodies 12 having different screw pitches of the feed screw mechanism 43 and different valve orifice diameters, which will be described later.

[0037] Furthermore, since the assembly 21 includes all the gears and also has a guide member 37 that supports the output shaft 36, it is possible to conduct test inspections such as operation tests and performance inspections of the gear section that slows down the rotation of the electric motor 51, thereby further improving the reliability of the electric valve 11.

[0038] The connecting member 40, which connects the electric motor 51 and the valve body 12, is a cylindrical member having a large diameter hole 40a and a small diameter hole 40b that are through holes that communicate with each other. The large diameter hole 40a passes through the upper center of the connecting member 40 and has a large diameter so that a bearing member 44 (described later) can be inserted from above. The small diameter hole 40b passes through the lower center of the connecting member 40 and has a small diameter. A can 42 is joined to the outer circumferential surface of the upper end of the connecting member 40 via a ring-shaped base plate 41.

[0039] A bearing member 44 is inserted and fixed in the large diameter hole 40a at the top of the connection member 40. The bearing member 44 is a cylindrical member having a central hole penetrating in the vertical direction, and a female screw (female screw portion) 44a is formed on the inner peripheral surface of the central hole. A screw drive member 45 is provided in the central hole of the bearing member 44. A male screw (male screw portion) 45a that screws into the female screw portion 44a of the bearing member 44 is formed on the outer peripheral surface of the screw drive member 45, and the male screw portion 45a (screw drive member 45) and the female screw portion 44a (bearing member 44) constitute the aforementioned feed screw mechanism, i.e., the transmission mechanism 43 that converts the rotational motion supplied from the stepping motor 51 via the gear device 22 into linear motion in the vertical direction and transmits it to the valve body 18.

[0040] Here, the output gear 30 rotates at a constant position in the vertical direction without moving up and down, and a flat screwdriver-shaped plate-like portion 45b provided at the upper end of a screw drive member 45 is inserted into a slit-shaped fitting groove 36a provided at the lower end of an output shaft 36 connected to the output gear 30 to transmit the rotational motion of the output gear 30 to the screw drive member 45. The plate-like portion 45b provided on the screw drive member 45 slides up and down within the fitting groove 36a of the output shaft 36, so that when the output gear 30 (rotor 24) rotates, the screw drive member 45 moves linearly up and down by the transmission mechanism (feed screw mechanism) 43, even though the output gear 30 does not move up and down.

[0041] The linear motion of the screw drive member 45 is transmitted to the valve body 18 via a ball joint 46 consisting of a ball 47 and a ball seat 48, and a spring receiving member 49. The valve body 18 is composed of a valve body main body 18a that moves toward and away from the valve seat 17, and a stepped cylindrical valve shaft 18b that rises upward from the center of the upper surface of the valve body main body 18a. The upper end of the valve shaft 18b is inserted into a fitting hole (lower surface fitting hole) 49a formed in the center of the lower surface of the spring receiving member 49 to connect the spring receiving member 49 and the valve body 18 (valve shaft 18b). A fitting hole (upper surface fitting hole) 49b is also provided in the center of the upper surface of the spring receiving member 49, and the ball seat 48 is fitted into this upper surface fitting hole 49b. Furthermore, the spring receiving member 49 is inserted into the small diameter hole 40b of the connection member 40 so as to be movable up and down.

[0042] The valve body support member 19 and the connection member 40 are screwed into the top opening of the valve body 12 in this order to close the top opening of the valve chamber. The valve body support member 19, which is fixed to the top of the valve chamber 13, has a stepped through hole in its center, through which the valve stem 18b passes so as to be vertically slidable, and in which a compression coil spring 50 is installed. The compression coil spring 50 is provided between the step at the top of the through hole and the spring receiving member 49. The compression coil spring 50 constantly biases the valve body 18 upward (in the valve opening direction) via the spring receiving member 49. As a result, even when the screw driving member 45 moves upward, the screw driving member 45 and the valve body 18, which are in contact with each other via the ball joint 46, do not separate, and the screw driving member 45 and the valve body 18 are integrated in the vertical direction. Furthermore, when the valve is opened, the biasing force of the compression coil spring 50 is applied to the valve body 18 in addition to the driving force of the electric motor 51, so that the valve opening operation can be performed more reliably.

[0043] The screw drive member 45 on the drive section side rotates and slides about the central axis A relative to the valve body 18 via the ball 47, and the rotation of the screw drive member 45 is not transmitted to the valve body 18. In this embodiment, the valve body 18, the spring receiving member 49, the ball joint 46 (ball 47 and ball seat 48), the screw drive member 45, the bearing member 44, the output shaft 36, the central shaft 27, the guide member 37, the orifice 16 (valve seat 17), the valve body support member 19, the connection member 40, the rotor 24, and other members are arranged coaxially, and the central axis A of these members coincides with the rotation axis (central axis) A of the rotor 24.

[0044] The operation of the motor-operated valve according to this embodiment will be described as follows.

[0045] When a current is supplied to the stator 52 (coil 55) so that the rotor 24 rotates in one direction from the closed valve state shown in Fig. 1, the rotation of the rotor 24 is converted into linear motion by the transmission mechanism 43, and the screw drive member 45 is pulled upward. As a result, the spring receiving member 49, which is pressed against the lower surface of the screw drive member 45 via the ball joint 46 by the urging force of the compression coil spring 50, and the valve shaft portion 18b connected to the spring receiving member 49 are pulled upward, and the valve body portion 18a is separated from the valve seat 17, opening the orifice 16, and the refrigerant that has flowed in from the inlet passage 14 passes through the valve chamber 13 and flows out from the outlet passage 15 (see arrow F in Fig. 4). The amount of refrigerant passing through (flow rate) in this open valve state can be adjusted by the amount of rotation of the rotor 24.

[0046] On the other hand, when a current is supplied to the stator 52 (coil 55) so that the rotor 24 rotates in the opposite direction from the open valve state, the rotation of the rotor 24 is converted into linear motion by the transmission mechanism 43, and the screw drive member 45 moves downward. With this downward movement, the ball joint 46, the spring receiving member 49, and the valve body 18 move downward, and when the valve body portion 18a abuts against the valve seat 17, the orifice 16 is closed, blocking the flow path between the inflow path 14 and the outflow path 15, and the valve is closed (see FIG. 1).

[0047] Second Embodiment A motor-operated valve according to a second embodiment of the present invention will be described with reference to Figures 5 to 8. In the description of this embodiment, the same or corresponding configurations as those in the first embodiment will be denoted by the same reference numerals, and duplicated descriptions will be omitted, with differences being mainly described.

[0048] 5 to 8, the motor-operated valve 61 according to this embodiment includes an assembly (gear device assembly) 21 including a gear device 22 as in the first embodiment, but includes a rotation detection means that detects the rotation of the screw drive member 45 by utilizing the space between the gear device 22 and the transmission mechanism 43. Since the rotation detection means is provided, in this embodiment, the gear case 23 has a longer vertical dimension than in the first embodiment, and the gear case 23 has a shape in which the peripheral wall extends downward.

[0049] Specifically, the rotation detection means comprises a disk-shaped driving permanent magnet 62 fixed to the screw drive member 45 so as to be positioned at the inner lower end of the gear case 23, a ring-shaped driven permanent magnet 63 positioned outside the lower outer circumferential surface of the gear case 23, and a magnetic sensor 64 that detects the rotation of the driven permanent magnet 63.

[0050] The driving permanent magnet 62 extends horizontally outward from the outer circumferential surface of the screw driving member 45 in a flange-like shape, and rotates together with the screw driving member 45. The driving permanent magnet 62 also has semicircular arc portions 62a and 62b that are partitioned by diameters (see FIG. 7). In one semicircular arc portion 62a, one N pole and one S pole are arranged in order from the inside to the outside in the radial direction, and in the other semicircular arc portion 62b, one S pole and one N pole are arranged in order from the inside to the outside in the radial direction. In this embodiment, the screw driving member 45 has a shaft portion 45c for fixing the driving permanent magnet 62 between the male screw portion 45a and the plate-shaped portion 45b, and therefore the screw driving member 45 of this embodiment has a longer overall length in the vertical direction than that of the first embodiment.

[0051] The driven permanent magnet 63 is coupled to the driving permanent magnet 62 by a magnetic coupling that transmits torque by utilizing the attractive force of a permanent magnet, and receives a rotational force from the driving permanent magnet 62 to rotate together with the driving permanent magnet 62. For this reason, the driven permanent magnet 63 has the following structure.

[0052] The driven permanent magnet 63 has an annular (ring) shape and has semicircular arc portions 63a and 63b that are partitioned by a diameter. In one semicircular arc portion 63a, one N pole and one S pole are arranged in order from the inside to the outside in the radial direction, and in the other semicircular arc portion 63b, one S pole and one N pole are arranged in order from the inside to the outside in the radial direction. The N pole of the driving permanent magnet 62 and the S pole of the driven permanent magnet 63 face each other with the peripheral wall of the gear case 23 in between, and the S pole of the driving permanent magnet 62 and the N pole of the driven permanent magnet 63 face each other with the peripheral wall of the gear case 23 in between, thereby forming a magnetic coupling between the driving permanent magnet 62 and the driven permanent magnet 63.

[0053] Furthermore, in order to support the driven permanent magnet 63 rotatably and slidably on the outer circumferential surface of the gear case 23, the following support structure is provided.

[0054] A ring-shaped protrusion 65 (extending around the entire circumference of the peripheral wall of the gear case 23) is formed at the lower end of the peripheral wall of the gear case 23 by protruding the peripheral wall outward. In addition, a recessed groove 66 (extending around the entire circumference of the inner peripheral surface of the driven permanent magnet 63) into which the protrusion 65 can be fitted is formed on the inner peripheral surface of the driven permanent magnet 63. These protrusions 65 and recessed grooves 66 allow the driven permanent magnet 63 to be supported on the outer peripheral surface of the gear case 23 in a slidable and rotatable manner without falling off the gear case 23 (for example, dropping downward).

[0055] Incidentally, the driving permanent magnet 62 fixed to the screw drive member 45 moves up and down while rotating together with the screw drive member 45 in accordance with the up and down movement of the screw drive member 45 (opening and closing of the valve). However, by making the up and down dimension of the driven permanent magnet 63 larger than that of the driving permanent magnet 62, even if the driving permanent magnet 62 moves up and down, the driving permanent magnet 62 does not go out of the up and down range of the driven permanent magnet 63 (a state facing the driven permanent magnet 63), and the magnetic coupling between the driving permanent magnet 62 and the driven permanent magnet 63 is not dissolved.

[0056] The magnetic sensor 64 is a rotation angle sensor that outputs a signal corresponding to the rotation angle of the magnetic field, and is disposed outside the can 42 so as to face radially the outer circumferential surface of the driven permanent magnet 63 across the peripheral wall of the can 42. The magnetic sensor 64 detects the magnetism of the driven permanent magnet 63 and outputs a signal corresponding to the rotation angle of the driven permanent magnet 63. This makes it possible to detect the rotational displacement of the screw drive member 45, and according to this embodiment, it becomes possible to detect the opening degree of the valve (the distance between the valve body 18 and the valve seat 17) more accurately.

[0057] Other configurations and operations of the motor-operated valve 61 according to this embodiment are similar to those of the motor-operated valve 11 according to the first embodiment. [Explanation of symbols]

[0058] A Central axis (rotor axis) F Refrigerant flow 11,61 Motor-operated valve 12 Valve body 13 Valve chamber 14 Inlet pipe (first flow path) 15 Outlet pipe (second flow path) 16 Orifice 17 Valve seat 18 Valve body 18a Valve body 18b Valve stem 19 Valve body support member 20 Strainer 21 Gear assembly 22 Gearing (Planetary Gear Reduction Mechanism) 23 Gear case 24 Rotor 25 Rotor parts 26 Sun gear parts 27 Central shaft 28 Support member 29 Sun Gear 30 Output Gear 31 Career 32 Shaft 33 Planetary Gear 34 Ring gear (internal teeth fixed gear) 35 Internal gear 36 Output shaft 36a Fitting groove 37 Output shaft guide member (guide part) 37a Through hole of output shaft guide member 38 Convex portion (engagement convex portion) 39 Recess (engagement recess) 40 Connection member 40a Large diameter hole 40b small diameter hole 41 Base Plate 42 Can 43 Transmission mechanism (feed screw mechanism) 44 Bearing parts 44a Female thread 45 Screw drive member 45a Male thread 45b Plate-shaped part 45c Shaft (shaft for fixing driving permanent magnet) 46 Ball joint 47 Ball 48 Ball seat 49 Spring support member 49a Fitting hole (bottom fitting hole) 49b Fitting hole (top fitting hole) 50 Compression coil spring 51 Electric motor 52 Stator 53 York 54 Bobbin 55 Coil 56 Molded cover 62 Drive permanent magnet 62a, 62b, 63a, 63b Semicircular arc section 63 Driven permanent magnet 64 Magnetic Sensor 65 Protrusion 66 Groove

Claims

1. a valve body having a valve chamber therein; A first flow passage communicating with the valve chamber; A second flow passage communicating with the valve chamber; an orifice formed between the first flow path and the second flow path; a valve body that moves forward and backward relative to the orifice to change the opening degree of the orifice; a rotor constituting an electric motor for driving the valve body; a gear device for reducing the rotation of the rotor; an output shaft that outputs rotation reduced by the gear device; a transmission mechanism that converts rotation of the output shaft into linear motion and transmits the linear motion to the valve body; A cylindrical gear case that houses the gear device; A guide portion that rotatably supports the output shaft; Equipped with The output shaft, the guide portion, and the gear device are supported by the gear case. A motor-operated valve.

2. The gear device, the gear case, the output shaft, the guide portion, and the rotor are unitized as a gear device assembly. The motor-operated valve according to claim 1.

3. An engagement recess is provided on one of an inner circumferential surface of the gear case and an outer circumferential surface of the guide portion, The other of the inner peripheral surface of the gear case and the outer peripheral surface of the guide portion is provided with an engagement protrusion that fits into the engagement recess to prevent rotation of the guide portion. The motor-operated valve according to claim 1 or 2.

4. The guide portion is provided in the gear case by insert molding. The motor-operated valve according to claim 1 or 2.

5. The transmission mechanism includes: a screw drive member that rotates in response to the rotation of the output shaft and is movable forward and backward relative to the output shaft, and has a male thread portion on an outer circumferential surface; a bearing member having a female thread portion that screws into the male thread portion of the screw drive member; Including, The motor-operated valve is a driving permanent magnet housed in a lower portion of the gear case and fixed to the screw driving member so as to rotate together with the screw driving member; a driven permanent magnet disposed on an outer circumferential surface of a lower portion of the gear case so as to be coupled to the driving permanent magnet by a magnetic coupling and to receive a rotational force from the driving permanent magnet; A magnetic sensor for detecting rotation of the driven permanent magnet; It also has The motor-operated valve according to claim 1 or 2.

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