JP5075555B2 - Synthetic resin housing for valve devices - Google Patents

Description

  The present invention relates to a synthetic resin housing for a valve device used as a three-way switching valve, a four-way switching valve or the like for switching a flow path of a hot water supply system.

Conventionally, valve devices such as a three-way switching valve and a four-way switching valve are known for switching the flow of fluid. The valve housing in such a valve device is composed of a case main body and its cover case, and is generally joined together by screws through a sealing O-ring. In such a structure, the number of parts and the number of assembly steps are reduced. As a result, the assembly workability is poor. Therefore, for example, Patent Document 1 proposes that the case main body and its cover case are made of synthetic resin and are joined together using an ultrasonic welding technique.
Japanese Unexamined Patent Publication No. 2004-278631 (paragraphs 0003 to 0005, 0017 to 0019, FIGS. 2 to 4)

  When fixing a case body made of synthetic resin and its cover case by ultrasonic welding, problems that should be improved in terms of joint strength (peeling resistance) and airtightness between the case body and the cover case in known structures Had. In particular, since ultrasonic welding is performed in an annular region surrounding the flow path, it is necessary to treat the melted resin in the joining by ultrasonic welding, and the inside of the housing is a sliding contact portion with a passage of water or a valve body. Therefore, it is not preferable for the product that the molten resin protrudes inside as a foreign substance.

  Accordingly, an object of the present invention is to minimize the volume of molten resin in a synthetic resin housing for a valve device in which a synthetic resin case body and its cover case are joined and joined using ultrasonic welding technology. It is necessary to sufficiently and sufficiently increase the bonding strength (peeling resistance) and airtightness between the case main body and the cover case.

In order to achieve the above object, a synthetic resin housing for a valve device according to the present invention is provided with an annular protrusion and an annular groove on one joint surface portion of a synthetic resin case body and a cover case. The annular groove is provided adjacent to the direction substantially perpendicular to the pressing direction during ultrasonic welding, and the annular groove is a molten resin when the joint including the annular protrusion is melted by application of ultrasonic vibration. have a size a haunt of the outer peripheral surface of the annular projection is formed on the conical inclined surface facing the annular groove, the cover case is cylindrical portion to enter the receiving portion of the case body when combined attachment to the case body And a stepped portion projecting radially outward from the base portion of the shaft tube portion and facing the annular protrusion and the annular groove .
The annular protrusion before ultrasonic welding preferably has a triangular shape with the tip protruding as one apex, and the apex angle is an acute angle within a range of 45 to 60 degrees .

  According to the synthetic resin housing for a valve device according to the present invention, the volume of the molten resin is suppressed to the minimum necessary in the structure in which the synthetic resin case body and the cover case are joined and joined using the ultrasonic welding technique. However, it is possible to ensure a sufficiently high bonding strength (peeling resistance) and airtightness, and it can be applied to a valve device having a high fluid pressure. That is, since the resin melted at the time of ultrasonic welding at the tip of the annular protrusion is stored in the annular groove formed adjacent to the annular protrusion, the molten resin does not come out inside the switching valve as a foreign substance. Homogeneous welding is possible on the entire circumference of the region, and since the melted and solidified portion does not become linear, high bonding strength (peeling resistance) and hermetic sealing properties can be obtained.

  Hereinafter, preferred embodiments of a synthetic resin housing for a valve device according to the present invention will be described with reference to the accompanying drawings. This preferred embodiment is an example in which the synthetic resin housing according to the present invention is applied to a three-way switching valve as an example of a valve device, and the structure of this three-way switching valve will be described.

  In FIG. 1, a spherical valve body 10 is rotatably supported in a valve chamber 21 of the housing 20 of the three-way switching valve. The valve body 10 is formed with a flow path including an inflow path 11 and an outflow path 12 connected to the inflow path 11. The housing 20 includes a case main body 20a and a cover case 20c that is joined and joined to the case main body 20a by an ultrasonic welding technique described later. An inflow port 22 connected to the inflow path 11 and a first outflow port 23 as an outflow port are formed in the case body 20a. The housing 20 including the case main body 20a and the case cover 20c is formed of a synthetic resin such as SPS (syndiotactic polystyrene resin) that is lightweight and excellent in heat resistance and chemical resistance.

  As shown in FIGS. 1 and 3, the cover case 20c is formed with a second outlet 24 which is another outlet in this embodiment. The cover case 20c is fixed to the case main body 20a by ultrasonic welding at the base end portion 25 thereof. The base end portion 25 is welded to the annular welded portion 22a on the case body 20a side by an annular welded portion 25a. An annular valve body abutting portion 25b is formed inside the welded portion 25a at the base end portion 25, and the spherical valve body 10 is in contact with the valve body abutting portion 25b so as to be freely slidable. .

  A geared motor 30 as a drive unit for rotationally driving the valve body 10 is attached to the motor mounting part 26 of the housing 20. The valve shaft 31 connected to the output shaft of the geared motor 30 extends through a through hole 27 formed in the motor mounting portion 26 of the housing 20, and the tip is connected to the valve body 10. By driving the geared motor 30, the rotation of the valve shaft 31 is transmitted to the valve body 10, and the valve body 10 rotates in the valve chamber 21.

  The valve shaft 31 is formed with circumferential grooves 32 at a plurality of locations (two locations in the axial direction in the illustrated example), and O-rings 33 are fitted into the circumferential grooves 32. The O-ring 33 is in pressure contact with the inner peripheral surface of the through hole 27 and prevents fluid such as hot water in the valve chamber 21 from leaking outside through the through hole 27.

  By rotating the valve body 10, the outflow path 12 of the valve body 10 is communicated with the first outflow port 23 or the second outflow port 24, whereby the inflow port 22 is connected to the first outflow port 23 through the flow paths 11 and 12. Any one of the second outlets 24 can be selectively communicated.

  As shown in FIG. 1, in the housing 20 incorporating the valve body 10, the geared motor 30, the valve shaft 31, and the O-ring 33, the case body 20a and the cover case 20c are united and joined by an ultrasonic welding technique. . At the time of ultrasonic welding, while the cover holder 20c is pressed against the cover main body 20a, ultrasonic vibration from an ultrasonic oscillator (not shown) is applied to the cover case 20c, so that the resin at the joint between the two heats and melts. Next, the application of ultrasonic vibration is canceled, and the molten resin is solidified, and the case main body 20a and the cover case 20c are integrally joined.

  At this time, the holder 20c is pushed in the direction of the arrow into the insertion port 20b of the case body 20a while receiving the vibration, so that the annular welded portion of the base end portion 25 of the cover case 20c is also shown in FIG. 25a is welded at an annular welded portion 22a formed in the insertion port 20b of the case body 20a.

  As shown in FIG. 2, which is a state after the housing 20 is welded, the geared motor 30 is fixed to the motor mounting portion 26 of the housing 20 by a tap screw 34. Since the cover case 20c is fixed to the case main body 20a by ultrasonic welding at the base end portion 25, the cover case 20c is integrated with the case main body 20a without using a fixing tool such as a screw.

  In the state before ultrasonic welding, the case body 20a has an annular protrusion 35 and an annular groove 36 around the opening of the holder insertion port 20b substantially perpendicular to the direction in which ultrasonic vibration is applied, as shown in FIG. Adjacent to each other (vertical direction in FIG. 4). The annular projecting portion 35 has a triangular shape, as viewed in a cross section, with the apex 35a being a tip protruding integrally from the case body 20a to the opening side of the cover insertion port 20b. The inner peripheral surface extending into the cover insertion port 20b from the annular apex 35a of the annular protrusion 35 is a cylindrical surface 35b continuous with the inner peripheral surface of the cover insertion port 20b when viewed in this section triangle. The outer peripheral surface of the annular protrusion 35 extending outward from the apex 35a is a conical slope 35c.

  The angle of the apex 35a of the annular protrusion 35 is preferably an acute angle within a range of 45 to 60 degrees. This is because the minimum welding area for welding the case main body 20a and the cover case 20c is determined based on the product size and the required strength, but in order to ensure more stable joint strength (peeling resistance) and airtightness, The amount of pushing 20c into the insertion opening 20b is reasonably large, and a non-linearly spread annular welded portion is generated that will solidify again after the contact portion including the annular projection 35 is melted. Depending on what is preferred.

  Here, the pushing amount is a tip portion including the apex 35a of the annular protrusion 35 from a state in which the base end 25 of the cover case 20c is inserted into the holder insertion port 20b and is in contact with the apex 35a of the annular protrusion 35. This is a distance when the resin is pushed in to a predetermined depth while melting the resin (the cover case 20c side where the annular protrusion 35 abuts at this time is also partially heated and melted). The angle range of the apex 35a of the annular protrusion 35 is determined as a condition for appropriately managing the amount of pressing of the cover case 20c and securing a necessary welding area based on the technical knowledge about the ultrasonic welding technique. .

  In the case of a material capable of ensuring a desired molding dimensional accuracy, the angle of the vertex 35a can be set to a relatively large angle. In addition, in the case of a material in which the desired molding dimensional accuracy is difficult to obtain, it is desirable to set a relatively small angle so as to increase the pushing amount. If the tip angle of the annular projection 35 is larger than 60 degrees, the amount of resin pushed into the welded portion becomes too small, making it difficult or non-uniform to secure the weldability, airtightness, and weld strength. Further, if the tip angle of the annular protrusion 35 is made smaller than 45 degrees to make it more acute, the volume of the molten resin is increased, and there is a tendency that the molten resin is unnecessarily protruded into the product.

  An annular groove 36 is formed on the outer side in the radial direction of the conical surface 35 c of the annular protrusion 35, that is, at a position adjacent to the annular protrusion 35 in a direction perpendicular to the direction of applying ultrasonic vibration. The annular groove 36 has such a size that the molten resin at the time of ultrasonic welding flows into the tip of the annular projection 35 and becomes a pool for the molten resin. The inner peripheral surface 37 of the annular groove portion 36 is continuous with the peripheral end surface 39 thereof, and the peripheral edge 38 between the inner peripheral surface 37 and the end surface 39 is formed in a curved surface for easy mounting of the cover case. Yes.

  The base end portion 25 of the cover case 20c includes a shaft tube portion 40 that enters the cover insertion port 20b, and a step portion 42 that projects radially outward from the base portion of the shaft tube portion 40. Resin molding so that a slight gap 41 of, for example, 0.1 mm is formed between the inner peripheral surface of the cover insertion port 20b of the case body 20a and the outer peripheral surface of the shaft tube portion 40 of the cover case 20c. Has been. Thus, the case body 20a and the holder 20c are aligned in the radial direction, and a good guide in the insertion direction can be obtained during assembly. The step portion 42 has an end face 43 facing in the axial direction and a peripheral face 44 facing outward in the radial direction. The end face 43 of the stepped portion 42 faces the annular protrusion 35 and the annular groove 36 of the case body 20a. A peripheral edge 45 where the end surface 43 and the peripheral surface 44 of the stepped portion 42 intersect is formed in a small curved surface in order to facilitate the mounting of the cover case 20c. An end face 46 orthogonal to the axial direction is formed around the step portion 42.

Next, the process of ultrasonic welding of the cover case 20c to the case body 20a will be described.
Prior to ultrasonic welding, the valve body 10, the valve shaft 31, and the O-ring 33 are incorporated into the case body 20a. First, the cover case 20c is pushed into the cover insertion port 20b while the shaft tube portion 40 of the cover case 20c is inserted into the cover insertion port 20b of the case body 20a to guide the shaft tube portion 40. The step portion 42 of the cover case 20c comes into contact with the annular protrusion 35 of the case body 20a from the tip (vertex 35a) side of the triangular cross section. By pressing and applying ultrasonic vibration to the contact portion, the stepped portion 42 enters the annular groove portion 36 while melting the annular protrusion 35 and the resin in the contact portion. At this time, since the peripheral edges 38 and 45 are small curved surfaces, the step portion 42 can smoothly enter the annular groove 36.

  Since the tip of the annular protrusion 35 is a triangular apex 35a, the pressing of the cover case 20c proceeds quickly at the initial stage of the pressing of the cover case 20c. Even if an error occurs in the size of the annular protrusion 35 due to the forming accuracy, such an error is absorbed in an initial process in which the pushing operation proceeds relatively quickly.

  As the pressing of the cover case 20c progresses and the stepped portion 42 approaches the base of the annular protrusion 35, the resin melting proceeds while the contact area with the annular protrusion 35 increases. The molten resin produced by melting a part of the annular protrusion 35 and a part of the step part 42 in contact with the annular protrusion 35 is guided by the inclined surface 35 c and is formed adjacent to the radially outer side of the annular protrusion 35. It flows into the groove 36. At this time, since the gap 41 between the outer peripheral surface of the shaft tube portion 40 and the inner peripheral surface of the cover insertion port 20b is narrow, when the ultrasonic vibration is applied, the shaft tube portion 40 and the holder insertion port 20b collide with each other. It does not melt and the amount of molten resin is controlled appropriately. Although only a part 47 of the molten resin enters the gap 41, most of the molten resin is solidified in a state where it is accommodated in the annular groove 36 (the range shown by being filled). That is, most of the molten resin flows into the annular groove 36 and solidifies in a non-linear manner to improve the bonding strength (peeling resistance) and airtightness, and does not protrude into unnecessary portions.

  As described above, the gap 41 formed inside the annular protrusion 35 between the cover case 20c and the cover insertion port 20b is compared with the width of the annular groove 36 formed outside the annular protrusion 35. Since it is overwhelmingly narrow, the molten resin generated by the application of ultrasonic vibration does not flow out to the side of the gap 41 where resistance is strong, that is, the inside where the main part of the valve exists. Moreover, since the cross-sectional shape of the annular protrusion 35 is a triangular shape with a sharp tip, the amount of pressing of the cover case 20c can be easily managed. And the ultrasonic welding area | region (part painted black in FIG. 5) obtained by melt | dissolving and solidifying a required part is uniformly formed in the perimeter, and a more reliable improvement in airtightness and joining strength is achieved.

  In the state after the completion of the ultrasonic welding, as shown in FIG. 5, the cover case 20 c has an end surface 43 in which a part of the end surface 43 and a part of the annular protrusion 35 are melted at the stepped portion 42. The remaining portion enters the annular groove portion 36. In this state, the space portion of the annular groove portion 36 is a pool for molten resin, and the molten resin is solidified there. When the end surface 46 of the base end portion 25 of the cover case 20c comes into contact with the end surface 39 formed around the cover insertion port 20b, the pushing of the cover case 20c is finished. At this time, the application of vibration is finished, and the cover case 20c enters the case main body 20a by a predetermined amount, so that the valve body 10 comes into contact with the valve body contact portion 25b. Since the valve body 10 is formed of a softer material than the case member, ultrasonic vibration is absorbed, and the case cover 20c is not welded to the valve body 10 during ultrasonic welding.

[Modifications of the invention]
In the above-described embodiment, the annular protrusion 35 and the annular groove 36 are provided adjacent to the case body 20a side. However, the annular protrusion 35 and the annular groove 36 are provided adjacent to the cover case 20c. can do.
Moreover, in the said Example, although the annular groove part 36 is arrange | positioned on the outer side of the annular protrusion part 35, the annular groove part 36 can be made into inner side (center side), and the annular protrusion part 35 can also be arrange | positioned on the outer side. Further, in the above embodiment, the cover case 20c includes the fluid outlet 24, but it may be a simple cover member without an outlet.
Furthermore, the present invention is not limited to a three-way switching valve, but can be applied to a valve device that uses a synthetic resin housing.

It is an expanded side sectional view in the state before welding of the change-over valve of this embodiment. It is a side view in the state after welding of the switching valve shown in FIG. FIG. 2 is a plan sectional view passing through the valve center of the switching valve shown in FIG. 1. It is an expanded sectional view which shows the principal part of a case main body and a holder in the state before welding of the switching valve shown in FIG. It is an expanded sectional view which shows the main part of a case main body and a holder in the state after welding of the switching valve shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Valve body 11 Inflow path 12 Outflow path 20 Housing 20a Case main body 20b Cover insertion port 20c Cover case 21 Valve chamber 22 Inflow port 22a Welding part 23 1st outflow port 24 2nd outflow port 25 Base end part 25a Joint part 25b Valve body Contact portion 26 Motor mounting portion 27 Through hole 30 Geared motor 31 Valve shaft 32 Circumferential groove 33 O-ring 35 Annular projection 35a Vertex 35b Cylindrical inner surface 35c Conical surface 36 Annular groove portion 37 Inner peripheral surface 38 Peripheral edge 39 End surface 40 Axis Cylindrical part 41 Gap 42 Step part 43 End face 44 Peripheral surface 45 Perimeter 46 End face 47 Part of resin

Claims (2)

A synthetic resin case body in which a housing in a valve device having a fluid inlet and an outlet and having a valve body rotatably disposed therein for switching the fluid flow is joined and joined together by ultrasonic welding technology And synthetic resin cover case,
One joint surface portion between the case body and the cover case is provided with an annular protrusion and an annular groove.
The annular protrusion and the annular groove are provided adjacent to a direction substantially perpendicular to the pressing direction during ultrasonic welding,
The annular groove may have a haunt become the size of the molten resin when the joint portion including the annular protrusion is melted by application of ultrasonic vibration,
The outer peripheral surface of the annular protrusion is formed as a conical slope facing the annular groove,
The cover case includes a shaft tube portion that enters the receiving portion of the case body when the unit body is attached to the case body, and projects radially outward from a base portion of the shaft tube portion so as to face the annular protrusion and the annular groove portion. A synthetic resin housing for a valve device.   The annular protrusion before ultrasonic welding has a triangular shape with a tip protruding as one apex, and the apex angle has an acute angle within a range of 45 to 60 degrees. A synthetic resin housing for a valve device according to claim 1.

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