Electrically driven valve and method for manufacturing electrically driven valve

Abstract

The present invention provides a method for manufacturing an electrically driven valve comprising a cylindrical valve body 17 having a valve chamber therein, a valve seat member 20 that has a valve seat 23 and that is joined to the bottom surface of the valve body, a first flow passage pipe 18 joined to a side surface of the valve body so as to communicate with the valve chamber, a second flow passage pipe 19 joined to the valve body bottom surface via a valve seat member so as to communicate with the valve chamber, a valve body 24 that moves toward and away from the valve seat, and a drive part that drives the valve body, said method comprising a valve body assembly manufacturing step for manufacturing a valve body assembly 14 in which the valve body and the first flow passage pipe have been joined (e.g., brazed), a valve seat assembly manufacturing step for manufacturing a valve seat assembly 15 in which the valve seat member and the second flow passage pipe have been joined (e.g., brazed), and a flow passage formation part manufacturing step for joining (e.g., welding) the valve body included in the valve body assembly and the valve seat member included in the valve seat assembly subsequent to the valve body assembly manufacturing step and the valve seat assembly manufacturing step.

Description

Electrically driven valve manufacturing method and electrically driven valve

[0001] The present invention relates to a method for manufacturing an electrically driven valve and an electrically driven valve.

[0002] Electrically driven valves, such as motor-operated valves that use an electric motor such as a stepping motor to control the valve opening degree, and electromagnetic valves that use a solenoid to control the valve opening degree, have traditionally been used in refrigeration cycle devices equipped with refrigerant circuits, such as air conditioners, refrigerators, and refrigeration devices.

[0003] An example of such a conventional electrically driven valve is an electric valve shown in Figure 13. As shown in the figure, this electric valve comprises a flow path forming section 12 that forms a refrigerant flow path including an orifice 22, a flow path control section 13 that controls the opening degree of the flow path (orifice 22), and a can (sealed container) 16 that hermetically covers the flow path control section 13.

[0004] The flow path forming portion 12 has a cylindrical valve body 17 having a valve chamber 21 therein, a valve seat member 20 having an orifice 22 (valve seat 23) and joined to the bottom surface of the valve body 17, a first flow path pipe 18 joined to the side surface of the valve body 17 so as to communicate with the valve chamber 21, and a second flow path pipe 19 joined to the bottom surface of the valve body 17 so as to communicate with the valve chamber 21 via the valve seat member 20.

[0005] On the other hand, the flow path control unit 13 has a valve element 24 provided so as to be movable toward and away from the orifice 22 (valve seat 23), a valve element support member 26 that movably supports the valve element 24, a connection member 25 that connects the flow path forming unit 12 and the flow path control unit 13, and a drive unit that drives the valve element 24. The drive unit has a rotor 36 that constitutes an electric motor, a speed reduction mechanism 39 that reduces the speed of rotation of the rotor 36, and a transmission mechanism 27 that converts the rotation reduced by the speed reduction mechanism 39 into linear motion and transmits it to the valve element.

[0006] In manufacturing, the flow path forming portion 12 and the flow path control portion 13 are assembled separately, and then these are joined together by welding together with the can 16 to form an integrated unit. The assembly of the flow path forming portion 12 is carried out in the following procedure.

[0007] First, as shown in Figure 14, the valve seat member 20 is press-fitted into the bottom surface of the valve body 17. Next, as shown in Figures 15 and 16, the first flow tube 18 is inserted into a hole drilled in the side surface of the valve body 17 and then fixed by crimping. The first flow tube 18 can be positioned in the insertion direction (axial direction of the first flow tube 18) by abutting it against the side surface of the valve seat member 20. Before inserting it into the hole in the valve body 17, a ring-shaped brazing material 42 is provided on the outer circumferential surface of the first flow tube 18.

[0008] 17 , the second flow path pipe 19 is inserted into the bottom opening of the valve seat member 20, and the valve body 17 is placed upside down and upright on a pedestal-shaped jig 55. As with the first flow path pipe 18, a ring-shaped brazing filler metal 42 is provided on the outer circumferential surface of the second flow path pipe 19 before it is inserted into the valve seat member 20, and a ring-shaped brazing filler metal 42 is also provided at the boundary between the valve body 17 and the valve seat member 20. The jig 55 has a flat pedestal portion 55a, a columnar portion 55b that rises from the top surface of the pedestal portion 55a and is inserted into the top opening of the valve body 17, and a support portion 55c that supports the tip of the first flow path pipe 18 from below.

[0009] The flow path forming portion 12 assembled as described above (the valve body 17, the valve seat member 20, and the flow path pipes 18, 19) is then integrated by furnace brazing. That is, the flow path forming portion 12 supported by the jig 55 is placed in a furnace, and the first flow path pipe 18 and the valve seat member 20 are joined to the valve body 17 by brazing, and the second flow path pipe 19 is joined to the valve seat member 20 by brazing.

[0010] Incidentally, a document disclosing a conventional motor-operated valve is Patent Document 1 listed below.

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 2018-071643

[0012] However, in the manufacturing process of the motor-operated valve, because there are many parts that must be joined to the flow path forming portion 12 so as to maintain airtightness, the management of each component before brazing and the brazing process are complicated, making it difficult to increase productivity. For example, the first flow path pipe 18 joined to the side of the valve body 17 is cantilevered relative to the valve body 17, and there is a risk that it will tilt (sag) due to gravity during brazing. For this reason, accuracy and care are required in the installation work on the jig 55. In addition, the jig 55 used must also be highly accurate so that it can hold the valve body 17 vertically and accurately support the second flow path pipe 18 horizontally so that it is perpendicular to the valve body 17.

[0013] Furthermore, since the conventional flow path forming portion 12 has a complex shape in which the first flow path pipe 18 protrudes horizontally from the valve body 17, it cannot be said that the utilization efficiency within the brazing furnace is good, and from this point of view as well, there is room for improvement in productivity.

[0014] Furthermore, there are various types of motor-operated valves with respect to the specifications of the valve seat member 20 (surface treatment and shape of the valve seat 23) and the specifications (shape and dimensions) of the flow path pipe (particularly the second flow path pipe 19) joined to the valve seat member 20, and it is necessary to prepare flow path forming parts 12 with these various different specifications in advance as inventory, but flow path forming parts 12 with complex shapes such as those described above take up space and the efficiency of using storage space is low.

[0015] The above-mentioned problems are not pointed out in the above-mentioned Patent Document 1, and cannot be solved by the invention described in the document. Similar problems also exist in conventional solenoid valves.

[0016] SUMMARY OF THE INVENTION Therefore, an object of the present invention is to improve the productivity of electrically driven valves and to increase the efficiency of storing parts.

[0017] In order to solve the above problems and achieve the object, the method for manufacturing an electrically driven valve according to the present invention is a method for manufacturing an electrically driven valve comprising: a cylindrical valve body having an internal valve chamber and open at the top and bottom; a valve seat member having a valve seat and joined to the bottom surface of the valve body; a first flow path pipe joined to the side surface of the valve body so as to communicate with the valve chamber; a second flow path pipe joined to the bottom surface of the valve body via the valve seat member so as to communicate with the valve chamber; a valve disc that moves forward and backward relative to the valve seat; and a drive unit that drives the valve disc, the method comprising: a valve body assembly manufacturing step of manufacturing a valve body assembly by joining the valve body and the first flow path pipe; a valve seat assembly manufacturing step of manufacturing a valve seat assembly by joining the valve seat member and the second flow path pipe; and a flow path forming portion manufacturing step of joining the valve body included in the valve body assembly and the valve seat member included in the valve seat assembly after the valve body assembly manufacturing step and the valve seat assembly manufacturing step. The order in which the valve body assembly fabrication process and the valve seat assembly fabrication process are carried out is not particularly important (either may be carried out first, or they may be carried out simultaneously).

[0018] In the method for manufacturing an electrically driven valve of the present invention, instead of simultaneously joining and integrating the valve body, valve seat member, and each of the flow path pipes (first flow path pipe and second flow path pipe) as a flow path forming portion as in the conventional manufacturing method described above, a valve body assembly, in which the valve body and the first flow path pipe are joined, and a valve seat assembly, in which the valve seat member and the second flow path pipe are joined, are separately manufactured (as separate components). Both of these assemblies (the valve body assembly and the valve seat assembly) have simpler shapes than conventional flow path forming portions (they are simply two members joined together in a linear shape, with no significant lateral protrusions; in other words, the flow path pipes, which are relatively long members, do not have shapes that extend in directions perpendicular to each other).

[0019] Therefore, for example, if furnace brazing is performed with the flow path pipes in a vertical position, there is no need to support the horizontally protruding portion (the flow path pipe) with a jig, as in the conventional method, and the joining work can be performed with good workability. Furthermore, when mass-producing each assembly (valve body assembly and valve seat assemblies), the assemblies can be placed closely spaced in the furnace, which improves furnace utilization efficiency and productivity. Furthermore, it becomes possible to store inventory in the form of each assembly with space efficiency.

[0020] In the present invention, the joining of the valve body and the first flow pipe in the valve body assembly manufacturing step, and the joining of the valve seat member and the second flow pipe in the valve seat assembly manufacturing step are both typically performed by brazing.

[0021] Furthermore, the joining of the valve body (valve body assembly) and the valve seat member (valve seat assembly) in the flow path forming portion fabrication process may be performed by, for example, welding. If the joining is performed by welding rather than furnace brazing, the valve seat will not be placed in a high-temperature furnace, and therefore it is possible to apply a coating, for example, a coating of PTFE (polytetrafluoroethylene) or other materials to the valve seat. The same applies to the electrically driven valve according to the present invention, which will be described next.

[0022] Furthermore, an electrically driven valve according to the present invention is an electrically driven valve comprising: a cylindrical valve body having an internal valve chamber and open at its top and bottom, a valve seat member having a valve seat and joined to the bottom surface of the valve body, a first flow path pipe joined to the side surface of the valve body so as to communicate with the valve chamber, a second flow path pipe joined to the bottom surface of the valve body via the valve seat member so as to communicate with the valve chamber, a valve disc that moves toward and away from the valve seat, and a drive unit that drives the valve disc, wherein the valve body and the valve seat member are joined by welding. Note that, as with the manufacturing method of the electrically driven valve according to the present invention, in this electrically driven valve as well, the valve body and the first flow path pipe are typically joined by brazing, and the valve seat member and the second flow path pipe are joined by brazing.

[0023] According to the present invention, it is possible to improve the productivity of electrically driven valves and increase the efficiency of storing parts.

[0024] Other objects, features, and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments of the present invention, which is given with reference to the accompanying drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

[0025] FIG. 1 is a longitudinal sectional view showing a motor-operated valve (closed state) according to a first embodiment of the present invention. FIG. 2 is a longitudinal sectional view showing a motor-operated valve (open state) according to the first embodiment. FIG. 3 is a diagram showing a step of a method for manufacturing the motor-operated valve according to the first embodiment (a state in which a first flow path pipe is inserted into a valve body in a valve body assembly manufacturing step). FIG. 4 is a diagram showing a step of a method for manufacturing the motor-operated valve according to the first embodiment (a state in which a valve body assembly is set in a jig). FIG. 5 is a diagram showing a step of a method for manufacturing the motor-operated valve according to the first embodiment (a state in which a second flow path pipe is inserted into a valve seat member in a valve seat assembly manufacturing step). FIG. 6 is a diagram showing a step of a method for manufacturing the motor-operated valve according to the first embodiment (a state in which a valve seat assembly is set in a jig). FIG. 7 is a diagram showing another example of a jig that can be used in the method for manufacturing the motor-operated valve according to the first embodiment (a step for manufacturing a valve seat assembly). FIG. 8 is a diagram showing a step of a method for manufacturing the motor-operated valve according to the first embodiment (a state before final assembly of the motor-operated valve). FIG. 9 is a longitudinal sectional view showing a motor-operated valve (closed state) according to a second embodiment of the present invention. FIG. 10 is a diagram showing a step of a manufacturing method for the motor-operated valve according to the second embodiment (a state in which a second flow path pipe is inserted into a valve seat member in a manufacturing step of a valve seat assembly). FIG. 11 is a diagram showing a step of a manufacturing method for the motor-operated valve according to the second embodiment (a state in which a valve seat assembly is set in a jig). FIG. 12 is a longitudinal sectional view showing a motor-operated valve according to a third embodiment of the present invention (in a closed state). FIG. 13 is a longitudinal sectional view showing an example of a conventional motor-operated valve. FIG. 14 is a diagram showing an example of a manufacturing method for a conventional motor-operated valve (a first step for manufacturing a flow path forming portion). FIG. 15 is a diagram showing an example of a manufacturing method for a conventional motor-operated valve (a second step for manufacturing a flow path forming portion). FIG. 16 is a diagram showing an example of a manufacturing method for a conventional motor-operated valve (a third step for manufacturing a flow path forming portion). FIG. 17 is a diagram showing an example of a manufacturing method for a conventional motor-operated valve (a fourth step for manufacturing a flow path forming portion).

[0026] [First embodiment] A motor-operated valve according to a first embodiment of the present invention and a method for manufacturing the same will be described with reference to Figures 1 to 8. Note that in each figure, mutually orthogonal two-dimensional coordinate axes representing the up-down and left-right directions are appropriately displayed, and the following description will be based on these directions. However, the motor-operated valve of this invention and this embodiment can be used in various orientations, and the directions are used for the convenience of explanation, and the configuration of each part of the present invention is not limited in any way by these directions.

[0027] [Structure of Motor-Operated Valve] As shown in Figures 1 to 8 (see Figures 1 and 8 in particular), 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 similar to the conventional motor-operated valve described above, comprises a flow path forming section 12 that forms a refrigerant flow path including an orifice 22, a flow path control section 13 that controls the opening degree of the orifice 22, and a can (sealed container) 16 that covers the flow path control section 13 in a sealed state.

[0028] The flow path forming portion 12 has a cylindrical valve body 17 having a valve chamber 21 therein and having an open top surface (upper surface) and bottom surface (lower surface), a valve seat member 20 having an orifice 22 and joined to the bottom surface of the valve body 17 so as to close the bottom opening of the valve body 17, a first flow path pipe 18 that penetrates the peripheral wall of the valve body 17 and is joined to the side surface of the valve body 17 so as to communicate with the valve chamber 21, and a second flow path pipe 19 that is joined to the bottom surface of the valve seat member 20 so as to communicate with the valve chamber 21 via the valve seat member 20.

[0029] The orifice 22 is a through-hole that passes through the valve seat member 20 in the vertical direction, and a valve seat 23 is formed on the upper surface of the orifice 22, with which a valve element 24 comes into contact and separates (abuts and separates).

[0030] Furthermore, the flow path forming portion 12 is not manufactured as an integrated part as in conventional motor-operated valves, but is manufactured separately into a valve body assembly 14 consisting of a valve body 17 and a first flow path pipe 18, and a valve seat assembly 15 consisting of a valve seat member 20 and a second flow path pipe 19, and these are then joined together in the final assembly process to form an integrated unit. This point will be described in detail later in the explanation of the manufacturing method.

[0031] On the other hand, the flow path control unit 13 has a valve element 24 that is arranged in the valve chamber 21 so as to be able to move back and forth (up and down) relative to the valve seat 23 (orifice 22), a valve element support member 26 that supports the valve element 24 so as to be able to move up and down, a connecting member 25 that is joined to the top surface of the valve body 17 so as to close the top opening of the valve body 17 and connects the flow path forming unit 12 and the flow path control unit 13, and a drive unit that drives the valve element 24.

[0032] The drive unit also has a rotor 36 that constitutes an electric motor (stepping motor), a speed reduction mechanism 39 that reduces the speed of the rotor 36, and a transmission mechanism 27 that converts the rotation reduced by the speed reduction mechanism 39 into linear motion and transmits it to the valve body, and the rotor 36, speed reduction mechanism 39, and transmission mechanism 27 are housed inside a can 16 that is joined to the upper surface of the connecting member 25. A stator (not shown) that constitutes the electric motor (stepping motor) together with the rotor 36 is provided on the outside of the can 16.

[0033] The rotor 36 is rotatably supported by a shaft 38 extending vertically through the center of the interior of the can 16. The upper end of the shaft 38 is supported by a support member 37 arranged on the inner ceiling of the can 16, and the lower end is supported by being inserted onto an output shaft 41, which will be described later. Inside the rotor 36, a paradox planetary gear mechanism having a high reduction ratio and advantageous for miniaturization is provided as the reduction mechanism 39. The rotation of the rotor 36 is reduced in speed by the reduction mechanism 39 and transmitted to an output shaft 41 connected to an output gear 40 arranged at the center of the underside of the rotor 36, and output from the output shaft 41.

[0034] The connecting member 25 joined to the upper surface of the valve body 17 is a ring-shaped member with a through-hole in the center, into which a valve body support member 26 for supporting the valve body 24 is fitted. The valve body support member 26 has a valve body support member main body 26a in the shape of a cylindrical container with a bottom and no lid, and a cylindrical cylinder portion 26c that hangs down vertically from the underside of a bottom plate portion 26b of the valve body support member main body 26a. The valve body support member main body 26a supports the valve body upper portion 24b that penetrates the bottom plate portion 26b so that it can slide up and down. The cylinder portion 26c supports the valve body lower portion 24a (the upper portion of the valve body lower portion 24a) so that it can slide up and down.

[0035] A cylindrical bearing member 28 is inserted into the upper part of the valve disc support member 26, and the bearing member 28 is fixed by crimping the upper surface of the valve disc support member 26. An output gear 40 is in slidable contact with the upper surface of the bearing member 28. The upper part of a stepped cylindrical output shaft 41 is press-fitted into the center of the bottom of the output gear 40, and the lower part of the output shaft 41 is rotatably inserted into a fitting hole 28b formed in the center of the upper surface of the bearing member 28. The lower end of a shaft 38 is rotatably fitted into the upper part of the output shaft 41.

[0036] A female thread 28a is formed in the lower center portion of the bearing member 28, and a male thread 29a formed on the outer peripheral surface of the screw drive member 29 is threadedly engaged with this female thread 28a. The feed screw mechanism 27, which is made up of the bearing member 28 (female thread 28a) and the screw drive member 29 (male thread 29a), constitutes a transmission mechanism that converts the rotational motion supplied from the electric motor (rotor 36) via the reduction mechanism 39 into linear motion in the vertical direction and transmits it to the valve disc 24.

[0037] Here, the output gear 40 rotates at a fixed position in the vertical direction without moving up and down, and a flat plate-like portion 29b provided at the upper end of the screw drive member 29 is inserted into a slit-like fitting groove 41a provided at the lower end of the output shaft 41 connected to the output gear 40, thereby transmitting the rotational motion of the output gear 40 to the screw drive member 29. As the plate-like portion 29b provided on the screw drive member 29 slides up and down inside the fitting groove 41a of the output shaft 41, when the output gear 40 (rotor 36) rotates, the screw drive member 29 moves linearly up and down by the feed screw mechanism 27, even though the output gear 40 and output shaft 41 do not move up and down.

[0038] The linear motion of this screw drive member 29 is transmitted to the valve element 24 via a ball joint 31 consisting of a ball 32 and a ball seat 33 fitted into a fitting hole 24d provided in the center of the top surface of the valve element upper part 24b. The valve element 24 consists of an upper valve element part 24b that penetrates the bottom plate part 26b of the valve element support member main body 26a, and a lower valve element part 24a that is arranged in the cylinder part 26c and the valve chamber 21. The upper valve element part 24b penetrates the bottom plate part 26b of the valve element support member main body 26a and also penetrates the bottom plate part 34a of the spring receiving member 34 that is arranged on the inner bottom surface of the valve element support member main body 26a, and has a head part 24c with an expanded diameter like a flange at its upper end.

[0039] The spring receiving member 34 has a bottom plate portion 34a that allows the valve disc upper portion 24b to pass through and abuts against the lower peripheral edge portion of the head portion 24c from below, a cylindrical peripheral wall portion 34c that forms a ring-shaped gap with the inner peripheral surface of the valve disc support member main body 26a, and a flange portion 34b that extends horizontally outward from the upper end of the peripheral wall portion 34c. A compression coil spring 35 is provided between the flange portion 34b of the spring receiving member 34 and the bottom plate portion 26b of the valve disc support member main body 26a.

[0040] This compression coil spring 35 constantly biases the valve body 24 (the head portion 24c of the valve body upper portion 24b) upward via the bottom plate portion 34a of the spring receiving member 34. As a result, even when the screw drive member 29 moves upward, the screw drive member 29 and the valve body 24, which are in contact via the ball joint 31, do not separate, and the screw drive member 29 and the valve body 24 are integrated in the vertical direction.

[0041] The screw drive member 29 on the drive unit side rotates and slides about the central axis A relative to the valve element 24 via the ball 32, and the rotation of the screw drive member 29 is not transmitted to the valve element 24. Furthermore, the second flow path pipe 19, valve seat member 20, valve seat 23 (orifice 22), valve body 17, valve element 24, valve element support member 26, ball joint 31, screw drive member 29, output shaft 41, bearing member 28, connecting member 25, shaft 38, and can 16 are all coaxially arranged, and the central axis A of these components coincides with the rotational axis (central axis) A of the rotor.

[0042] [Operation of Motor-Operated Valve] The operation of the motor-operated valve according to this embodiment will be described as follows.

[0043] When current is supplied to the stator (not shown) so that the rotor 36 rotates in one direction from the closed valve state shown in FIG. 1 , the rotation of the rotor 36 is converted into linear motion by the feed screw mechanism 27, and the screw drive member 29 is pulled upward. Accordingly, the valve element 24 (the head portion 24c of the valve element upper portion 24b), which is pressed against the underside of the screw drive member 29 via the ball joint 31 by the biasing force of the compression coil spring 35, is pulled upward, and the valve element 24 (the valve element lower portion 24a) moves away from the valve seat 23. Refrigerant flowing in from the first flow tube 18 passes through the valve chamber 21 and the orifice 22 and flows out of the second flow tube 19 (see arrow F in FIG. 2 ). 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 36 (the distance between the valve seat 23 and the valve element 24).

[0044] On the other hand, when a current is supplied to the stator so that the rotor 36 rotates in the opposite direction from the open valve state, the rotation of the rotor 36 is converted into linear motion by the feed screw mechanism 27, and the screw drive member 29 moves downward. As this downward movement occurs, the valve element 24 moves downward, and when the valve element 24 (valve element lower part 24a) abuts against the valve seat 23, the orifice 22 is closed and the flow path between the first flow pipe 18 and the second flow pipe 19 is blocked, resulting in a closed valve state (see FIG. 1).

[0045] In the above description of the operation, the refrigerant flows in through the first flow pipe 18 and flows out through the second flow pipe 19, but it is also possible to use the motor-operated valve 11 so that the refrigerant flows in through the second flow pipe 19 and flows out through the first flow pipe 18. Furthermore, the drive unit does not necessarily need to include the speed reduction mechanism 39, and the present invention can also be applied to a so-called direct-acting motor-operated valve in which the rotation of the electric motor (rotor) is converted into linear motion by a transmission mechanism without going through a speed reduction mechanism, thereby directly moving the valve element up and down.

[0046] [Method for Manufacturing Motor-Operated Valve] The method for manufacturing the motor-operated valve according to this embodiment will be described below.

[0047] 3 and 4 , the first flow pipe 18 is inserted into a hole drilled in the side of the valve body 17, and a ring-shaped brazing filler metal 42 is placed on the outer peripheral surface of the base end of the first flow pipe 18 (the portion protruding into the valve body 17) (see FIG. 3 ). Then, a pedestal-shaped jig 51 is inserted into the first flow pipe 18 from its tip end (see FIG. 4 ). The jig 51 has a flat base portion 51a and a columnar portion 51b that stands vertically upward from the top surface of the base portion 51a, and can support the first flow pipe 18 in a vertically standing state by inserting the columnar portion 51b into the first flow pipe 18. In this supported state, the tip of the columnar portion 51b abuts against the inner surface of the valve body 17, thereby supporting the valve body 17 from below.

[0048] Then, while supported by the jig 51 in this manner, the valve body 17 and the first flow path pipe 18 are placed in a furnace, and the valve body 17 and the first flow path pipe 18 are joined (brazed) to form a single unit, and then the jig 51 is removed to produce the valve body assembly 14.

[0049] 5, the valve seat member 20 is turned upside down, and the second flow path pipe 19 is inserted into the bottom opening of the valve seat member 20. At this time, a ring-shaped brazing filler metal 42 is provided on the outer circumferential surface of the second flow path pipe 19. The valve seat member 20 with the second flow path pipe 19 inserted is then set on a pedestal-shaped jig 52 as shown in FIG. 6. This jig 52 has a recess 52a into which the valve seat member 20 can be fitted, and by fitting the valve seat member 20 into this recess 52a, it is possible to maintain the valve seat member 20 with the second flow path pipe 19 inserted in an upright position so that it does not fall over.

[0050] It is to be noted that a jig 53 as shown in Fig. 7 may be used instead of the jig 52. The jig 53 shown in Fig. 7 has a flat base portion 53a and a columnar portion 53b that rises vertically from the center of the top surface of the base portion 53a, and by inserting the columnar portion 53b into the orifice 22 of the valve seat member 20, it is possible to provide support similar to that of the jig 52 in Fig. 6.

[0051] Then, the valve seat member 20, into which the second flow path pipe 19 has been inserted and which has been supported by the jig 52 (or jig 53) as described above, is placed in a furnace, and the valve seat member 20 and the second flow path pipe 19 are joined (brazed) together to form a single unit. After that, the jig 52 (or jig 53) is removed to produce the valve seat assembly 15.

[0052] In addition, the flow path control section 13 is assembled separately from the valve body assembly 14 and the valve seat assembly 15 .

[0053] Then, as the final assembly process of the motor-operated valve 11, the valve seat assembly 15, the valve body assembly 14, the flow path control section 13 and the can 16 are joined together to form an integrated unit.

[0054] Specifically, as shown in Figure 8, a valve seat assembly 15, a valve body assembly 14, a flow path control portion 13, and a can 16 are prepared, the valve seat member 20 of the valve seat assembly 15 is inserted into the bottom opening of the valve body 17 of the valve body assembly 14, the flow path control portion 13 is inserted into the top opening of the valve body 17 of the valve body assembly 15, and the can 16 is placed over the flow path control portion 13 (the order of these steps is not particularly important). Then, the lower end of the can 16 is joined to the upper edge of the connecting member 25, the upper edge of the valve body 17 to the stepped portion on the outer peripheral surface of the middle portion of the connecting member 25, and the lower edge of the valve body 17 to the outer peripheral portion of the valve seat member 20 are joined by welding. These joining points are indicated by reference numeral 43 in Figure 1.

[0055] Furthermore, laser welding, which produces little thermal distortion and provides high joint strength, can be preferably used for the above welding. Furthermore, when laser welding is used, in the motor-operated valve of this embodiment, the outer diameters of the can 16, connecting member 25, valve body 17, and valve seat member 20 are all equal, and the distances (horizontal distances) between the laser head (laser focusing device) that focuses the laser light on the welding points and each welding point are equal. Therefore, each welding point can be efficiently joined by simply moving the laser head vertically (toward the central axis A of the motor-operated valve 11). Note that the welding method in the present invention is not limited to laser welding; for example, TIG welding or other welding methods can also be used.

[0056] Furthermore, welding (including welding other than laser welding) can avoid exposing the valve seat portion 20 to high heat compared to furnace brazing, and therefore makes it possible to apply a coating (even if it is made of a coating material that is relatively heat-sensitive) to the valve seat 23 in advance. The coating material used for the valve seat is preferably one whose main component is PTFE (polytetrafluoroethylene), which improves lubricity between the valve body and the coating material, thereby suppressing wear and making it possible to prevent valve leakage.

[0057] 9 to 11, a motor-operated valve and a manufacturing method thereof according to a second embodiment of the present invention will be described. In the description of this embodiment, the same or corresponding components as those in the first embodiment will be denoted by the same reference numerals, and redundant description will be omitted, with the focus being on differences (the same applies to a third embodiment described later).

[0058] 9, the motor-operated valve 61 according to this embodiment includes a flow path forming portion 62 and a flow path control portion 13, similar to the motor-operated valve 11 according to the first embodiment, and the flow path forming portion 62 is made up of a valve body assembly 14 and a valve seat assembly 63. However, the second flow path 19 extends horizontally to the right so that the refrigerant can flow horizontally into the valve chamber 21 from the left side and flow horizontally to the right side. Accordingly, the structure of the valve seat assembly 63 differs from that of the first embodiment.

[0059] More specifically, the valve seat assembly 63 in this embodiment has a block-shaped valve seat member 64 that is taller than the valve seat member 20 of the first embodiment and is L-shaped so that the orifice 22 extends vertically downward from the bottom surface of the valve chamber (valve seat 23) and then bends at a right angle to the right. An opening that communicates with the orifice 22 is formed in the side surface (right surface) of the valve seat member 64, and the second flow path pipe 19 is joined to this opening.

[0060] 10 and 11 , the second flow pipe 19 is inserted into a hole drilled in the side surface of the valve seat member 64, and then a pedestal-shaped jig 54 is used to support the second flow pipe 19 so that it stands upright with the valve seat member 64 facing up. The jig 54 is similar to the jig 51 (see FIG. 4 ) used in the first embodiment, and has a columnar portion 54b that is inserted into the second flow pipe 19 and whose tip 54c abuts against the inner circumferential surface of the valve seat member 64 (orifice 22), and a flat pedestal portion 54a that supports the second flow pipe 19, which is inserted into the columnar portion 54b and stands upright, so that it does not tip over. In addition, a ring-shaped brazing filler metal 42 is arranged on the base end of the second flow pipe 19 (the end inserted into the valve seat member 64).

[0061] Then, the valve seat member 64, into which the second flow path pipe 19 has been inserted and which has been supported by the jig 54 as described above, is placed in a furnace, and the valve seat member 64 and the second flow path pipe 19 are joined (brazed) to form a single unit. After that, the jig 54 is pulled out to produce the valve seat assembly 63.

[0062] Furthermore, similarly to the first embodiment, the valve body assembly 14 and the flow path control section 13 are assembled, and then these are joined by welding to the valve seat assembly 63 and the can 16 to complete the motor-operated valve 61. Note that the components other than the valve seat assembly 63, including the valve body assembly 14, are the same as those in the first embodiment, and the motor-operated valve 61 of this embodiment can be manufactured by simply changing the valve seat assembly 63.

[0063] [Third embodiment] As shown in Figure 12, an electric valve 71 according to a third embodiment of the present invention includes a flow path forming portion 72 and a flow path control portion 13, similar to the electric valve 11 according to the first embodiment, and the flow path forming portion 72 is made up of a valve body assembly 14 and a valve seat assembly 73. However, the shape of the second flow path 74 is different so that the refrigerant can flow horizontally from the left side into the valve chamber 21 and flow out horizontally in the same direction (to the left).

[0064] Specifically, in this embodiment, the second flow path pipe 74 has an L-shape that extends vertically downward from the lower surface of the valve seat member 20, then bends at a right angle and extends horizontally to the left.

[0065] The motor-operated valves 11, 61, and 71 of the first to third embodiments can be manufactured simply by changing the valve seat assembly 15, 63, and 73 used in the final assembly process. Therefore, even if motor-operated valves with specifications that require different directions of the flow pipes through which refrigerants flow in and out depending on the location of use are required, the present invention can flexibly accommodate such requirements. Furthermore, the valve body assembly 14, which is a common part, has a relatively simple shape and does not require much storage space, so it can be manufactured in large quantities and stocked.

[0066] Although the embodiments of the present invention have been described above, it will be apparent to those skilled in the art that the present invention is not limited to the above embodiments and that various modifications can be made within the scope of the claims.

[0067] For example, while the above embodiment has been described using an example of a motor-operated valve, the present invention can of course also be applied to the valve body of a solenoid valve. In this case, the drive unit is a solenoid having a coil, an attractor, and a plunger, and the valve element is configured to open and close the orifice (valve seat) in conjunction with the plunger. In this application, motor-operated valves and solenoid valves are collectively referred to as electrically operated valves.

[0068] DESCRIPTION OF SYMBOLS A Central axis (rotor rotation axis) 11, 61, 71 Motor-operated valve 12, 62, 72 Flow path forming portion 13 Flow path control portion 14 Valve body assembly 15, 63, 73 Valve seat assembly 16 Can 17 Valve body 18 First flow path pipe 19, 74 Second flow path pipe 20, 64 Valve seat member 21 Valve chamber 22 Orifice 23 Valve seat 24 Valve body 24a Lower part of valve body 24b Upper part of valve body 24c Head portion 24d Fitting hole 25 Connecting member 26 Valve body support member 26a Valve body support member main body 26b Bottom plate portion 26c Cylinder portion 27 Transmission mechanism (feed screw mechanism) 28 Bearing member 28a Female thread portion 28b Fitting hole 29 Screw drive member 29a Male thread portion 29b Plate-shaped portion 31 Ball-shaped joint 32 Ball 33 Ball seat 34 Spring receiving member 34a Bottom plate portion 34b Flange portion 34c Peripheral wall portion 35 Compression coil spring 36 Rotor 37 Support member 38 Shaft 39 Reduction mechanism 40 Output gear 41 Output shaft 41a Fitting groove 42 Brazing material 43 Welded portion 51, 52, 53, 54, 55 Jig 51a, 53a, 54a, 55a Base portion 51b, 53b, 54b, 55b Column-shaped portion 51c, 54c Tip of column-shaped portion 52a Recessed portion 55c Support portion

Claims

1. A method for manufacturing an electrically driven valve comprising: a cylindrical valve body having an internal valve chamber and open at the top and bottom; a valve seat member having a valve seat and joined to the bottom surface of the valve body; a first flow path pipe joined to a side surface of the valve body so as to communicate with the valve chamber; a second flow path pipe joined to the bottom surface of the valve body via the valve seat member so as to communicate with the valve chamber; a valve disc that moves forward and backward relative to the valve seat; and a drive unit that drives the valve disc, comprising: a valve body assembly fabrication step of fabricating a valve body assembly by joining the valve body and the first flow path pipe; a valve seat assembly fabrication step of fabricating a valve seat assembly by joining the valve seat member and the second flow path pipe; and a flow path forming unit fabrication step of joining the valve body included in the valve body assembly and the valve seat member included in the valve seat assembly after the valve body assembly fabrication step and the valve seat assembly fabrication step.

2. A method for manufacturing an electrically driven valve as described in claim 1, wherein the joining of the valve body and the first flow pipe in the valve body assembly manufacturing process, and the joining of the valve seat member and the second flow pipe in the valve seat assembly manufacturing process are both performed by brazing.

3. A method for manufacturing an electrically driven valve as set forth in claim 1 or 2, wherein the valve body and the valve seat member are joined by welding in the flow passage forming portion fabrication process.

4. An electrically driven valve comprising: a cylindrical valve body having an internal valve chamber and open at the top and bottom; a valve seat member having a valve seat and joined to the bottom surface of the valve body; a first flow path pipe joined to a side surface of the valve body so as to communicate with the valve chamber; a second flow path pipe joined to the bottom surface of the valve body via the valve seat member so as to communicate with the valve chamber; a valve disc that moves forward and backward relative to the valve seat; and a drive unit that drives the valve disc, wherein the valve body and the valve seat member are joined by welding.

5. The electrically driven valve according to claim 4, wherein the valve body and the first flow pipe are joined by brazing, and the valve seat member and the second flow pipe are joined by brazing.

Images