CN112005036B - Flow path switching valve and method for manufacturing same - Google Patents

Abstract

Provided are a flow path switching valve and a method for manufacturing the flow path switching valve, wherein the degree of freedom of the structure of a valve body can be effectively improved. A flow path switching valve (1) is provided with: the valve comprises a resin valve body (10) provided with a valve chamber (14), a rotatable ball valve (20) housed in the valve chamber (14), a drive section (40) having a drive mechanism for rotating the ball valve (20), and a valve shaft (50) for connecting the ball valve (20) to the drive mechanism. The drive unit (40) has a resin drive unit case (42) that houses the drive mechanism. The drive section case (42) is joined to the valve main body (10).

Description

Flow path switching valve and method for manufacturing same

Technical Field

The present invention relates to a flow path switching valve and a method for manufacturing the same.

Background

Patent document 1 discloses an example of a conventional flow path switching valve. In this flow path switching valve, the spherical valve body is rotatably housed in a valve housing as a valve main body. A gear motor that drives the ball valve body to rotate via the valve shaft is attached to the valve housing. In addition, the valve housing is provided with one inlet flow passage and two outlet flow passages communicating with the valve chamber. The flow path switching valve selectively connects the inlet flow path with either of the two outlet flow paths in accordance with a rotational position of the ball valve element.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2010-223418

Technical problem to be solved by the invention

Such a flow path switching valve can be applied to various apparatuses while suppressing costs by sharing the gear motor, the valve shaft, and the valve body and changing the configuration of the valve housing such as the arrangement of the inlet flow path and the outlet flow path. However, since a mounting structure such as a screw fixing structure or a snap-fit structure for mounting the gear motor needs to be provided in the valve housing, the degree of freedom of the structure of the valve housing may be limited.

Disclosure of Invention

Accordingly, an object of the present invention is to provide a flow path switching valve and a method of manufacturing the flow path switching valve that can effectively improve the degree of freedom of the structure of the valve body.

Means for solving the problems

In order to achieve the above object, a flow path switching valve according to an aspect of the present invention includes: a valve body made of resin, the valve body being provided with a valve chamber and a plurality of flow paths communicating with the valve chamber; a valve body which is housed in the valve chamber and is rotatable, and which switches the connection of the flow path according to a rotational position; a drive unit having a drive mechanism for rotating the valve body; and a valve shaft that connects the valve body and the drive mechanism, wherein the drive unit includes a resin-made drive unit case that houses the drive mechanism, and the drive unit case is joined to the valve main body.

According to the present invention, the resin-made drive section case accommodating the drive mechanism for rotating the valve body is joined to the valve body. In this way, only the joint portion with the drive section case in the valve main body needs to be shared, and therefore, the portion restricted in design can be minimized, and the degree of freedom in the structure of the valve main body can be effectively improved.

In the present invention, the drive unit case is ultrasonically welded or infrared-welded to the valve main body. Thus, compared to bonding with an adhesive, for example, it is not necessary to consider the amount of the adhesive applied and the unevenness of the application, and the drive section case and the valve main body can be easily bonded. Further, since the interior of the drive unit case and the valve main body can be welded, the welded portion can be prevented from being exposed.

In the present invention, the valve body has a valve shaft insertion hole into which the valve shaft is inserted, and the valve shaft insertion hole is formed so as to rotate the valve body in accordance with rotation of the valve shaft. Thus, the valve body and the valve shaft can be separated from each other, and the timing for inserting the valve shaft into the valve shaft insertion hole and coupling the valve body and the valve shaft can be selected at the time of assembly. For example, the valve shaft may be inserted into a valve body, and then the valve body and the drive unit case may be joined and welded to each other. Alternatively, the valve body may be housed in the valve body, the valve shaft may be supported by the drive section case, and the valve body may be joined and welded to the drive section case while the valve shaft is inserted into the valve shaft insertion hole. This makes it possible to select an assembly procedure that is less susceptible to welding.

In the present invention, the drive section housing integrally includes a bearing section into which the valve shaft is inserted, the valve shaft includes an annular closing member that closes a gap between the valve shaft and the bearing section, the valve body is disposed so that the valve shaft insertion hole faces the bearing section with a gap therebetween, and the valve shaft includes a valve body side stopper surface that abuts against the valve body when the valve shaft is inserted into the valve shaft insertion hole. This prevents the valve shaft from being inserted too deeply into the valve shaft insertion hole during assembly.

In the present invention, it is preferable that the flow path switching valve is configured such that a distance from the seal portion of the seal member to the end surface on the valve element side in the bearing portion is shorter than a distance from the stop surface on the valve element side to the valve element. In the case of ultrasonic welding, when the closing member comes into contact with the bearing portion when ultrasonic waves are applied to the drive portion case, the closing member may melt and adhere to the bearing portion, or the closing member may be damaged. However, in the present invention, since the structure described above is provided, when the ultrasonic wave is applied to the drive section case, the valve element side stopper surface of the valve shaft can be brought into contact with the valve element, and the closing member can be disposed outside the bearing section. Therefore, the closing member can be prevented from adhering to or being damaged by the bearing portion. Even when infrared welding is employed, the valve shaft and the closing member can be prevented from coming off the bearing portion during welding by disposing the closing member outside the bearing portion.

In the present invention, it is preferable that the valve shaft has a bearing portion side stopper surface facing a side opposite to the valve body side stopper surface, and the bearing portion side stopper surface abuts against an end surface of the bearing portion on the valve body side when the valve shaft is inserted into the bearing portion. Thus, when a force is generated on the valve shaft from the valve element side toward the bearing portion side due to a pressure difference between the inside of the valve chamber and the atmosphere, the bearing portion side stopper surface abuts against the end surface of the bearing portion on the valve element side. Therefore, the valve shaft can be prevented from falling off.

In the present invention, it is preferable that an insertion portion of the valve shaft, into which the valve shaft insertion hole is inserted, is formed in a polygonal columnar shape, and the valve shaft insertion hole is formed in a shape identical to a cross-sectional shape of the insertion portion. Thus, the insertion portion of the valve shaft is fitted into the valve shaft insertion hole of the valve body, and the rotation of the valve shaft can be reliably transmitted to the valve body.

In the present invention, it is preferable that the valve body has a peripheral wall portion, the drive unit case has an annular wall portion inserted into the peripheral wall portion in a welding direction, and the flow path switching valve is configured such that an inner peripheral surface of the peripheral wall portion comes into contact with an outer peripheral surface of the annular wall portion when the drive unit case is welded to the valve body. Thus, when the drive unit case is moved in a direction (welding direction) closer to the valve main body and the welding portions are joined to each other during welding, the inner peripheral surface of the peripheral wall portion comes into contact with the outer peripheral surface of the annular wall portion, thereby restricting the drive unit case from moving in a direction orthogonal to the welding direction with respect to the valve main body. Therefore, the drive unit case and the valve main body can be prevented from being welded in a misaligned state.

In the present invention, it is preferable that a length of a contact portion between an inner peripheral surface of the peripheral wall portion and an outer peripheral surface of the annular wall portion in the welding direction is 1.5mm or more in a state before the drive portion case is welded to the valve main body. This can sufficiently secure a portion where the inner peripheral surface of the peripheral wall portion and the outer peripheral surface of the annular wall portion are in contact with each other, and can more effectively prevent the drive unit case and the valve body from being welded in a misaligned state.

In the present invention, it is preferable that at least one of a peripheral edge of the valve shaft insertion hole and a peripheral edge of an end surface of the valve shaft on the valve element side is provided with an annular tapered surface. Thus, even when the axes of the valve shaft are displaced from each other when the valve shaft is inserted into the valve shaft insertion hole, the valve shaft can be guided to the valve shaft insertion hole by the annular tapered surface, and the valve shaft insertion hole can be automatically aligned with each other.

In order to achieve the above object, according to another aspect of the present invention, there is provided a method of manufacturing a flow path switching valve, including: a valve body made of resin, the valve body being provided with a valve chamber and a plurality of flow paths communicating with the valve chamber; a valve body which is housed in the valve chamber and is rotatable, and which switches the connection of the flow path according to a rotational position; a drive unit having a drive mechanism for rotating the valve body and a resin drive unit case for housing the drive mechanism; and a valve shaft that connects the valve body and the drive mechanism, wherein the drive section housing is joined to the valve body.

According to the present invention, the resin-made drive portion housing that houses the drive mechanism that rotates the valve element is joined to the valve main body. Accordingly, only the welding portion with the drive unit case in the valve main body can be shared, and the portion subject to design restrictions can be minimized, thereby effectively improving the degree of freedom in the structure of the valve main body.

In the present invention, the drive section housing integrally includes a bearing section into which the valve shaft is inserted, the valve shaft has an annular closing member that closes a gap between the valve shaft and the bearing section, the valve body has a valve shaft insertion hole into which the valve shaft is inserted to rotate the valve body in accordance with rotation of the valve shaft, the valve shaft has a valve body side stopper surface that abuts the valve body when the valve shaft is inserted into the valve shaft insertion hole, and the flow path switching valve is configured such that a distance from a closing portion of the closing member to a valve body side end surface in the bearing section is shorter than a distance from the valve body side stopper surface to the valve body, and the valve shaft is inserted into the valve shaft insertion hole of the valve body in the valve chamber, the valve body and the drive section case are joined to each other so that the valve shaft insertion hole faces the bearing section with a gap therebetween until the valve body side stopper surface abuts against the valve body, the drive section case is ultrasonically welded or infrared-welded to the valve body in a state where the closing member is positioned outside the bearing section, and the valve shaft is moved in the axial direction toward the bearing section side after the drive section case is welded to the valve body so that the closing member closes the gap. In the case of ultrasonic welding, when the closing member comes into contact with the bearing portion when ultrasonic waves are applied to the drive portion case, the closing member may melt and adhere to the bearing portion, or the closing member may be damaged. However, in the present invention, with the above-described configuration, when the ultrasonic wave is applied to the drive section case, the valve element side stopper surface of the valve shaft abuts against the valve element, and the closing member is disposed outside the bearing section. Therefore, the closing member can be prevented from adhering to or being damaged by the bearing portion. Even when infrared welding is employed, the valve shaft and the closing member can be prevented from coming off the bearing portion during welding by disposing the closing member outside the bearing portion.

In the present invention, it is preferable that the annular wall portion of the drive unit case is inserted into the inside of the peripheral wall portion of the valve main body in the welding direction so that the inner peripheral surface of the peripheral wall portion is in contact with the outer peripheral surface of the annular wall portion, and the drive unit case is ultrasonically welded or infrared-welded to the valve main body after the valve main body and the drive unit case are joined so that the length in the welding direction of the contact portion between the inner peripheral surface of the peripheral wall portion and the outer peripheral surface of the annular wall portion is 1.5mm or more. Thus, when the drive unit case is moved in a direction approaching the valve body (welding direction) and welded during welding, the inner peripheral surface of the peripheral wall portion comes into contact with the outer peripheral surface of the annular wall portion, whereby the drive unit case is restricted from moving in a direction orthogonal to the welding direction with respect to the valve body. Further, by setting the length in the welding direction of the contact portion between the inner peripheral surface of the peripheral wall portion and the outer peripheral surface of the annular wall portion to 1.5mm or more, a portion where the inner peripheral surface of the peripheral wall portion and the outer peripheral surface of the annular wall portion are in contact can be sufficiently secured. Therefore, the driving unit case and the valve main body can be effectively prevented from being welded by being displaced from each other.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, the degree of freedom of the structure of the valve main body can be effectively improved.

Drawings

Fig. 1 is a front view of a flow path switching valve according to a first embodiment of the present invention.

Fig. 2 is a longitudinal sectional view of the flow path switching valve of fig. 1.

Fig. 3 is a perspective view including a partial section of the flow path switching valve of fig. 1.

Fig. 4 is an exploded perspective view including a part of a cross section of the flow path switching valve of fig. 1.

Fig. 5 is a sectional view (a state where a valve shaft is inserted into a ball valve body) illustrating a method of manufacturing the flow path switching valve of fig. 1.

Fig. 6 is a sectional view (a state in which a valve main body is coupled to a drive unit casing) illustrating a method of manufacturing the flow path switching valve of fig. 1.

Fig. 7 is a cross-sectional view (a state where the valve shaft is moved to the bearing portion side) illustrating a method of manufacturing the flow path switching valve of fig. 1.

Fig. 8 is a sectional view (a state where a valve shaft is inserted into a ball valve body) illustrating a method of manufacturing a flow path switching valve according to a second embodiment of the present invention.

Fig. 9 is a sectional view (a state in which the valve main body is coupled to the drive unit casing) illustrating a method of manufacturing the flow path switching valve of fig. 8.

Fig. 10 is a cross-sectional view (a state where the valve shaft is moved to the bearing portion side) illustrating a method of manufacturing the flow path switching valve of fig. 8.

Fig. 11 is a cross-sectional view (a state where a valve shaft is inserted into a bearing) illustrating a method of manufacturing a flow path switching valve according to a third embodiment of the present invention.

Fig. 12 is a cross-sectional view (a state where the valve main body and the drive unit casing are irradiated with infrared rays) illustrating a method of manufacturing the flow path switching valve of fig. 11.

Fig. 13 is a sectional view (a state in which the valve main body is coupled to the drive unit case, before welding) illustrating a method of manufacturing the flow path switching valve of fig. 11.

Fig. 14 is a cross-sectional view (a state in which the valve main body is coupled to the drive unit case, after welding) illustrating a method of manufacturing the flow path switching valve of fig. 11.

Detailed Description

(first embodiment)

The configuration of a flow path switching valve according to a first embodiment of the present invention will be described below with reference to fig. 1 to 4.

Fig. 1 is a front view of a flow path switching valve according to a first embodiment of the present invention. Fig. 2 (a) is a cross-sectional view (vertical cross-sectional view) taken along the axial direction of the valve shaft of the flow path switching valve in fig. 1, and fig. 2 (b) is an enlarged view of a portion surrounded by a single-dot chain line in fig. 2 (a). Fig. 3 is a perspective view including a partial section of the flow path switching valve of fig. 1. Fig. 4 is an exploded perspective view including a partial cross section of the flow path switching valve of fig. 1. In the present specification, "upper, lower, left, and right" are used to indicate relative positional relationships between the respective members in the drawings, and do not indicate absolute positional relationships.

As shown in fig. 1 to 4, the flow path switching valve 1 of the present embodiment includes a valve main body 10, a ball valve element 20, support members 30 and 30, a drive unit 40, and a valve shaft 50.

The valve body 10 is made of synthetic resin and is formed in a substantially cubic box shape with an open upper portion. The valve main body 10 has a bottom wall portion 15 and a peripheral wall portion 16 connected to a peripheral edge portion of the bottom wall portion 15. The peripheral wall 16 includes a left side wall 10a, a front side wall 10b, a right side wall 10c, and a back side wall 10 d. The left side wall 10a is provided with a substantially L-shaped first flow path 11. The front wall 10b is provided with a linear second flow path 12. A third flow passage 13 having a substantially L-shape is provided in the right side wall portion 10 c. The opening 11a of the first channel 11, the opening 12a of the second channel 12, and the opening 13a of the third channel 13 face the same direction (front side, front side of the paper of fig. 1). The first flow path 11, the second flow path 12, and the third flow path 13 communicate with a valve chamber 14 provided in the valve main body 10. Two or more flow paths communicating with the valve chamber 14 may be provided.

The spherical valve body 20 is formed in a hollow spherical shape (spherical shape) using, for example, metal, synthetic resin, or the like as a material. The spherical valve body 20 is rotatably housed in the valve chamber 14 of the valve body 10. The ball valve core 20 is provided with a first opening 21 that opens toward the left side, a second opening 22 that opens toward the front, and a third opening 23 that opens toward the right side in the state shown in fig. 3. The first opening 21, the second opening 22 and the third opening 23 are connected to each other inside the ball valve core 20. In the present embodiment, the spherical valve body 20 is used as the valve body, but a columnar valve body may be used.

The ball valve element 20 connects the first flow path 11, the second flow path 12, and the third flow path 13 in the rotational position shown in fig. 3. In a rotational position in which the ball valve body 20 is rotated 90 degrees clockwise from the rotational position shown in fig. 3 in a plan view, the first flow path 11 and the second flow path 12 are connected. In a rotational position in which the ball valve body 20 is rotated 90 degrees counterclockwise from the rotational position shown in fig. 3 in a plan view, the second flow passage 12 and the third flow passage 13 are connected. The ball valve body 20 switches the connection of the first flow path 11, the second flow path 12, and the third flow path 13 according to the rotational position.

A valve shaft insertion hole 24 into which the valve shaft 50 is inserted is provided in an upper portion of the spherical valve body 20. The valve shaft insertion hole 24 is formed so that the ball valve body 20 rotates with the rotation of the valve shaft 50 by inserting the valve shaft 50. Specifically, the valve shaft insertion hole 24 is formed in the following shape: the shape is the same as the cross-sectional shape (cross-sectional shape) in the direction orthogonal to the axial direction in the prism portion 52 of the valve shaft 50.

The support members 30, 30 are made of, for example, synthetic resin, and are formed in an annular shape. The support members 30, 30 rotatably support the ball valve element 20 in the valve chamber 14 with the ball valve element therebetween. The support members 30, 30 seal (close) the space between the valve body 10 and the ball valve element 20 together with O- rings 31, 31 formed of a rubber material provided between the valve body 10.

The drive unit 40 includes a drive mechanism that couples a speed reducer including a motor and a gear 41, not shown, and a resin drive unit case 42 that houses the drive mechanism. The drive section case 42 is formed in a substantially rectangular parallelepiped box shape. The drive section case 42 has a lower case 43 and an upper case 44. The lower case 43 and the upper case 44 are attached to each other by an unillustrated attachment structure such as a screw fixing structure or a snap fit structure.

The lower case 43 integrally has a cylindrical bearing portion 45 at the center of the bottom wall 43 a. The bearing 45 is inserted with the valve shaft 50, and rotatably supports the valve shaft 50. Further, a rib 43b as an annular wall portion is provided on the bottom wall 43a of the lower case 43. The rib 43b is inserted inside the peripheral wall portion 16 of the valve main body 10. The rib 43b is formed to be fitted to the peripheral wall portion 16. The outer peripheral surface of the rib 43b contacts the inner peripheral surface of the peripheral wall portion 16. The ribs 43b are joined to the upper end portion of the peripheral wall portion 16 of the valve main body 10 and joined to each other at the welded portion M. In the present embodiment, the welded portion M is ultrasonically welded. Instead of ultrasonic welding, the welding portion M may be infrared-welded.

The valve shaft 50 has a cylindrical portion 51 and a prism portion 52 coaxially connected to a lower end of the cylindrical portion 51. The axis of the valve shaft 50 coincides with the axis L.

The cylindrical portion 51 is provided at its lower end portion with an annular stopper portion 53 that protrudes radially outward. The stopper portion 53 is formed so that its outer diameter is larger than the outer diameter of the cylindrical portion 51 and the inner diameter of the bearing portion 45. Thus, when the bearing 45 is inserted into the columnar portion 51, the bearing side stopper surface 53a, which is the upper surface of the stopper 53, abuts against the lower end surface 45a of the bearing 45 on the side of the ball valve element 20. During normal operation or no load, a gap (play) is provided between the lower end surface 45a of the bearing portion 45 and the bearing portion side stopper surface 53 a.

Further, a groove 51a is formed in the lower end portion of the columnar portion 51 over the entire circumference at a position above the stopper portion 53. A seal member 54 (O-ring) formed in an annular shape and made of a rubber material or the like is fitted into the groove 51 a. The cylindrical portion 51 is inserted into the bearing portion 45 and is rotatably supported by the bearing portion 45. The outer diameter of the cylindrical portion 51 is slightly smaller than the inner diameter of the bearing portion 45. When the cylindrical portion 51 is inserted into the bearing portion 45, the closing member 54 closes the gap between the valve shaft 50 and the bearing portion 45. Thereby, the fluid inside the valve chamber 14 is prevented from leaking to the outside.

The gear 41 of the driving unit 40 is fixedly attached to the upper end of the columnar unit 51 by press fitting. The valve shaft 50 rotates about the axis L as a rotation axis in accordance with the rotation of the gear 41. A flat portion is provided at an upper end portion of the cylindrical portion 51, and the flat portion suppresses idling of the gear 41 to be press-fitted.

The prism portion 52 is formed in a columnar shape having a cross-sectional shape of a regular hexagonal shape. The prism portion 52 is an insertion portion that is inserted into the valve shaft insertion hole 24 of the ball valve core 20. The valve shaft insertion hole 24 is formed in a regular hexagonal shape identical to the cross-sectional shape of the prism portion 52. Therefore, the valve shaft insertion hole 24 is fitted to the prism portion 52, and the spherical valve element 20 rotates with the rotation of the valve shaft 50. The prism portion 52 is formed to have a smaller outer diameter than the stopper portion 53. Thus, when the valve shaft insertion hole 24 is inserted into the prism portion 52, the valve body side stopper surface 53b, which is the lower surface of the stopper portion 53, abuts against the ball valve body 20.

In the present embodiment, the prism portion 52 is a column shape having a cross-sectional shape formed in a regular hexagonal shape, but is not limited thereto. The prism portion 52 may be a polygonal column such as a triangular column or a quadrangular column. The prism portion 52 may be a member having a shape other than a prism, or may be a columnar shape having a D-shaped cross section in which a part of a side surface of a columnar shape is a plane, for example. In this case, the valve shaft insertion hole 24 is also formed in the same shape as the cross-sectional shape of the prism portion 52.

As shown in fig. 2 (B), the flow path switching valve 1 is configured such that, in the axial direction of the valve shaft 50, a distance a from the closing point K of the closing member 54 to the lower end surface 45a on the side of the ball valve element 20 in the bearing portion 45 is shorter than a distance B from the valve element side stopper surface 53B to the ball valve element 20. With this configuration, when the prism portion 52 of the valve shaft 50 is inserted into the shaft insertion hole 24 of the ball valve core 20 until the valve core side stopper surface 53b abuts against the ball valve core 20, the closing member 54 is exposed to the outside of the bearing portion 45 and positioned in the valve chamber 14. In the present embodiment, the closed portion K corresponds to the center of the closing member 54 in the bearing portion 45 in the vertical direction, but the closed portion K may correspond to the upper wall portion of the groove 51a in the bearing portion 45.

In the flow path switching valve 1, the rotation of the motor of the drive unit 40 is output to the valve shaft 50 through the gear 41, and the valve shaft 50 rotates about the axis L as a rotation axis. The ball valve core 20 rotates in accordance with the rotation of the valve shaft 50 and is positioned at each rotational position. This realizes connection of the flow path corresponding to the rotational position.

Next, an example of a method for manufacturing the flow path switching valve 1 according to the present embodiment will be described with reference to fig. 5 to 7.

Fig. 5 to 7 are cross-sectional views for explaining a method of manufacturing the flow path switching valve of fig. 1, and show a state in which the valve shaft 50 is inserted into the ball valve body 20, a state in which the valve body 10 is coupled to the drive section housing 42, and a state in which the valve shaft 50 is moved to the bearing section 45 side in this order.

As shown in fig. 5, the prism portion 52 of the valve shaft 50 is inserted into the valve shaft insertion hole 24 of the spherical valve body 20 housed in the valve chamber 14 until the valve body side stopper surface 53b abuts against the spherical valve body 20.

Next, as shown in fig. 6, the valve body 10 is coupled to the lower housing 43 of the drive section housing 42 so that the valve shaft insertion hole 24 and the bearing section 45 face each other with a gap therebetween in the vertical direction. Specifically, the rib 43b is inserted into the inside of the peripheral wall portion 16 of the valve body 10 in the vertical direction (i.e., the direction in which the drive unit case approaches the valve body during welding (welding direction)), and the inner peripheral surface of the peripheral wall portion 16 is arranged in contact with the outer peripheral surface of the rib 43 b. Thereby, the upper end of the cylindrical portion 51 of the valve shaft 50 is inserted into the bearing 45, and the lower end of the cylindrical portion 51 is positioned outside the bearing 45. In this state, the closing member 54 is positioned in the valve chamber 14 below the bearing 45, and the closing member 54 does not abut against the bearing 45 and does not press the inside of the bearing 45. That is, in this state, the closing member 54 is positioned outside the bearing portion 45. The axial center of valve shaft 50 is aligned with the axial center of bearing 45 so that cylindrical portion 51 of valve shaft 50 does not contact bearing 45 (a gap is formed between bearing 45 over the entire circumference of the outer circumferential surface of cylindrical portion 51).

Next, in a state where the closing member 54 is positioned outside the bearing portion 45, ultrasonic waves are applied to the lower case 43 of the drive portion case 42, and the lower case 43 is ultrasonically welded to the valve main body 10. At this time, the lower case 43 is in contact with only the valve body 10, and is not in contact with the valve shaft 50 and the closing member 54, so that only the ultrasonic waves can be applied between the lower case 43 and the valve body 10. When the lower case 43 is welded to the valve main body 10, the inner peripheral surface of the peripheral wall portion 16 contacts the outer peripheral surface of the rib 43 b. Therefore, the lower case 43 is guided to move in the vertical direction by the peripheral wall portion 16 and the rib 43b, and movement in a direction orthogonal to the vertical direction is restricted. This enables the lower case 43 to be joined to the valve main body 10 with high accuracy.

Next, as shown in fig. 7, the valve shaft 50 is moved in the axial direction toward the bearing 45 so that the closing member 54 closes the gap between the valve shaft 50 and the bearing 45.

Then, the gear 41 is press-fitted into the upper end portion of the cylindrical portion 51 of the valve shaft 50, and the drive mechanism is assembled into the lower case 43 and the upper case 44 is closed, thereby completing the drive unit 40. In this way, the flow path switching valve 1 is completed.

As can be seen from the above, according to the flow path switching valve 1 of the present embodiment, the resin-made drive section housing 42 that houses the drive mechanism that rotates the ball valve element 20 is joined to the valve main body 10. Since the valve main body 10 does not have a top surface (wall surface on the drive unit housing 42 side), a part of the wall surface (bottom surface portion) of the drive unit housing 42 constitutes a wall surface (top surface) of the valve chamber after being welded to the drive unit housing 42. Accordingly, since only the welding portion with the drive unit case 42 in the valve main body 10 needs to be shared, the design-restricted portion can be minimized, and the degree of freedom in the structure of the valve main body 10 can be effectively improved.

In addition, the drive section case 42 is ultrasonically welded to the valve main body 10. This makes it possible to easily weld the interior of the drive unit case 42 and the valve main body 10, and thus to prevent the welded portion from being exposed. In addition, by using ultrasonic welding (or infrared welding), it is not necessary to consider the amount of application or unevenness of the adhesive, compared with, for example, bonding with an adhesive, and the drive unit case and the valve main body can be easily bonded.

Further, the ball valve core 20 has a valve shaft insertion hole 24 into which the valve shaft 50 is inserted. The valve shaft insertion hole 24 is formed to rotate the ball valve core 20 in accordance with the rotation of the valve shaft 50. Thereby, the ball valve body 20 and the valve shaft 50 are separate members and can be separated from each other. This makes it possible to select the timing of coupling the ball valve body 20 to the valve shaft 50 at the time of assembly. Therefore, an assembly order less susceptible to the influence of welding can be selected.

That is, the flow path switching valve 1 of the present embodiment is configured such that the ball valve body 20 and the valve shaft 50 are separate members, and the positional relationship therebetween can be changed at the time of assembly. For example, in a structure in which the ball valve body 20 and the valve shaft 50 are integrated, the positional relationship between the ball valve body 20 and the valve shaft 50 cannot be changed at the time of assembly. Therefore, when the valve main body 10 and the drive unit case 42 are ultrasonically welded, the respective members are arranged at the same positions as those at the completion of the flow path switching valve 1. Therefore, when ultrasonic waves are applied to the lower housing 43 for ultrasonic welding, vibrations caused by the ultrasonic waves are transmitted from the bearing portion 45 to the closing member 54, the valve shaft 50, the ball valve element 20, the support members 30, and the O- rings 31, 31 in this order. Thereby, the closing member 54 and the bearing portion 45, the ball valve body 20 and the support members 30, and the valve main body 10 and the O- rings 31, 31 rub against each other, and may be melted or damaged. Therefore, in the flow path switching valve 1 of the present embodiment, the positional relationship between the ball valve body 20 and the valve shaft 50 is changed at the time of assembly so that the vibration caused by the ultrasonic waves applied to the lower housing 43 is not transmitted to the closing member 54, the ball valve body 20, and the O- rings 31 and 31.

The drive section housing 42 integrally has a bearing section 45 into which the valve shaft 50 is inserted. The valve shaft 50 includes an annular closing member 54 that closes a gap with the bearing 45. The ball valve core 20 has a valve shaft insertion hole 24, and the valve shaft insertion hole 24 is disposed to face the bearing 45 with a gap therebetween, and is formed so that the ball valve core 20 rotates with the rotation of the valve shaft 50 by inserting the valve shaft 50. The valve shaft 50 has a valve body side stopper surface 53b, and when the valve shaft 50 is inserted into the valve shaft insertion hole 24, the valve body side stopper surface 53b abuts against the ball valve body 20. This prevents the valve shaft 50 from being inserted too deeply into the valve shaft insertion hole 24 during mounting. Further, the distance a from the closing portion K of the closing member 54 to the lower end surface 45a on the ball valve element 20 side in the bearing portion 45 is configured to be shorter than the distance B from the valve element side stopper surface 53B to the ball valve element 20. In the case of ultrasonic welding, when ultrasonic waves are applied to the drive portion case 42, the closing member 54 may melt and adhere to the bearing portion 45 or the closing member 54 may be damaged when the closing member 54 comes into contact with the bearing portion 45. In the flow path switching valve 1 of the present embodiment, since the ball valve core 20 and the valve shaft 50 are separate members and have the above-described configuration, when the ultrasonic wave is applied to the drive section case 42, the valve core side stopper surface 53b of the valve shaft 50 can be brought into contact with the ball valve core 20, and the closing member 54 can be disposed outside the bearing section 45. Therefore, the closing member 54 can be prevented from adhering to or damaging the bearing portion 45.

The valve shaft 50 has a bearing side stop surface 53a, the bearing side stop surface 53a faces the side opposite to the valve body side stop surface 53b, and when the valve shaft 50 is inserted into the bearing 45, the bearing side stop surface 53a abuts against the lower end surface 45a of the bearing 45 on the side of the ball valve body 20. Thus, when a force is generated from the ball valve body 20 side toward the bearing 45 side with respect to the valve shaft 50 due to a pressure difference with the atmosphere in the valve chamber 14, the bearing side stopper surface 53a abuts against the lower end surface 45a of the bearing 45. Therefore, the valve shaft 50 can be prevented from falling off.

In addition, in the valve shaft 50, a prism portion 52 into which the valve shaft insertion hole 24 is inserted is formed in a regular hexagonal column shape, and the valve shaft insertion hole 24 is formed in the same shape as the cross-sectional shape of the prism portion 52. Accordingly, the prism portion 52 of the valve shaft 50 is fitted into the valve shaft insertion hole 24, and the rotation of the valve shaft 50 can be reliably transmitted to the ball valve body 20.

The valve body 10 has a peripheral wall portion 16, and the drive portion case 42 has a rib 43b as an annular wall portion, and the rib 43b is inserted into the peripheral wall portion 16 in the vertical direction. When the drive unit case 42 is welded to the valve main body 10, the inner peripheral surface of the peripheral wall portion 16 is configured to contact the outer peripheral surface of the rib 43 b. Thus, during welding, the inner peripheral surface of the peripheral wall portion 16 contacts the outer peripheral surface of the rib 43b, and the movement of the drive unit case 42 in the direction perpendicular to the vertical direction with respect to the valve main body 10 is restricted. Therefore, the drive unit case 42 and the valve main body 10 can be welded while being prevented from being displaced.

(second embodiment)

Hereinafter, a flow path switching valve according to a second embodiment of the present invention will be described with reference to fig. 8 to 10.

The flow path switching valve 2 according to the second embodiment includes a valve shaft 50A, which is not provided with the stopper 53, instead of the valve shaft 50 in the flow path switching valve 1 according to the first embodiment described above. The other configuration is the same as that of the flow path switching valve 1, and the flow path switching valve 2 has the same configuration. The flow path switching valve 2 is provided with the same reference numerals as those of the flow path switching valve 1, and the description thereof is omitted.

Fig. 8 to 10 are cross-sectional views for explaining a method of manufacturing a flow path switching valve according to a second embodiment of the present invention, and show a state in which the valve shaft 50A is inserted into the ball valve core 20, a state in which the valve body 10 is coupled to the drive section housing 42, and a state in which the valve shaft 50A is moved to the bearing section 45 side in this order.

The valve shaft 50A includes a cylindrical portion 51 and a prism portion 52 coaxially connected to a lower end of the cylindrical portion 51. The axis of the valve shaft 50A coincides with the axis L.

The cylindrical portion 51 is formed to have an outer diameter smaller than that of the prism portion 52. In other words, when the valve shaft 50A is viewed from the direction of the axis L, the columnar section 51 is included in the projected area of the prismatic section 52. Thus, when the insertion of the columnar portion 51 into the bearing portion 45 is completed, the bearing portion side stopper surface 52a, which is the upper surface of the prism portion 52, abuts against the lower end surface 45a of the bearing portion 45 on the ball valve element 20 side.

The prism portion 52 is formed in a columnar shape having a cross-sectional shape of a regular hexagonal shape. The prism portion 52 is an insertion portion that is inserted into the valve shaft insertion hole 24 of the ball valve core 20. The valve shaft insertion hole 24 is formed in a regular hexagonal shape identical to the cross-sectional shape of the prism portion 52. Therefore, the valve shaft insertion hole 24 is fitted in the prism portion 52, and the ball valve body 20 rotates with the rotation of the valve shaft 50A. When the prism portion 52 is inserted into the valve shaft insertion hole 24, the valve body side stopper surface 52b, which is the lower surface of the prism portion 52, abuts against the ball valve body 20.

As shown in fig. 10, the flow path switching valve 2 is configured such that a distance a from the closing point K of the closing member 54 to the lower end surface 45a on the ball valve element 20 side in the bearing portion 45 is shorter than a distance B from the valve element side stopper surface 52B to the ball valve element 20. With this configuration, when the prism portion 52 of the valve shaft 50A is inserted into the shaft insertion hole 24 of the ball valve core 20 until the valve core side stopper surface 52b abuts against the ball valve core 20, the closing member 54 is positioned outside the bearing portion 45.

Next, an example of a method for manufacturing the flow path switching valve 2 according to the present embodiment will be described with reference to fig. 8 to 10.

As shown in fig. 8, the prism portion 52 of the valve shaft 50A is inserted into the valve shaft insertion hole 24 of the spherical valve element 20 housed in the valve chamber 14 until the valve element side stopper surface 52b abuts against the spherical valve element 20.

Next, as shown in fig. 9, the valve body 10 is coupled to the lower housing 43 of the drive section housing 42 so that the valve shaft insertion hole 24 and the bearing section 45 face each other with a gap therebetween in the vertical direction. Specifically, the rib 43b is inserted into the inside of the peripheral wall portion 16 of the valve main body 10 in the vertical direction, and the inner peripheral surface of the peripheral wall portion 16 is disposed in contact with the outer peripheral surface of the rib 43 b. Thereby, the upper end of the columnar portion 51 of the valve shaft 50A is inserted into the bearing portion 45, and the lower end of the columnar portion 51 is positioned outside the bearing portion 45. In this state, the closing member 54 is positioned in the valve chamber 14 below the bearing portion 45, that is, the closing member 54 is positioned outside the bearing portion 45. The axis of valve shaft 50A is aligned with the axis of bearing 45 so that cylindrical portion 51 of valve shaft 50A does not contact bearing 45 (a gap is formed between bearing 45 over the entire circumference of the outer circumferential surface of cylindrical portion 51).

Next, in a state where the closing member 54 is positioned outside the bearing portion 45, ultrasonic waves are applied to the lower case 43 of the drive portion case 42, and the lower case 43 is ultrasonically welded to the valve main body 10. At this time, the lower case 43 is in contact with only the valve body 10, and is not in contact with the valve shaft 50A and the closing member 54, so that the ultrasonic waves can be applied only between the lower case 43 and the valve body 10. When the lower case 43 is welded to the valve main body 10, the inner peripheral surface of the peripheral wall portion 16 contacts the outer peripheral surface of the rib 43 b. Therefore, the lower case 43 is guided to move in the up-down direction, and movement in a direction orthogonal to the up-down direction is restricted. This enables the lower case 43 to be joined to the valve main body 10 with high accuracy.

Next, the valve shaft 50A is moved in the axial direction toward the bearing 45 so that the closing member 54 closes the gap between the valve shaft 50A and the bearing 45.

Then, the gear 41 is press-fitted into the upper end portion of the columnar portion 51 of the valve shaft 50A, and the drive mechanism is assembled into the lower case 43 and the upper case 44 is closed, thereby completing the drive unit 40. In this way, the flow path switching valve 2 is completed.

The flow path switching valve 2 of the present embodiment can also exhibit the same operational advantages as the flow path switching valve 1 of the first embodiment described above.

The first and second embodiments described above have a structure in which the drive unit case 42 (specifically, the lower case 43) is ultrasonically welded to the valve main body 10. As the welding method, infrared welding may be used instead of ultrasonic welding. In this case, the respective welded portions of the drive unit case 42 and the valve main body 10 are heated by infrared rays, and then the respective welded portions of the drive unit case 42 and the valve main body 10 are brought into contact with each other and welded. Accordingly, only the welding portion with the drive unit case 42 in the valve main body 10 needs to be shared, and therefore, as in the case of ultrasonic welding, the design-restricted portion can be minimized, and the degree of freedom in the structure of the valve main body can be effectively increased.

(third embodiment)

A flow path switching valve according to a third embodiment of the present invention will be described below with reference to fig. 11 to 14.

The flow path switching valve 3 according to the third embodiment has a structure for welding the lower case 43 and the valve main body 10 by infrared welding instead of ultrasonic welding in the flow path switching valve 2 according to the second embodiment described above. The flow path switching valve 3 has the same configuration as the flow path switching valves 1 and 2 described above, and the same reference numerals are used to omit descriptions thereof.

Fig. 11 to 14 are sectional views for explaining a method of manufacturing a flow path switching valve according to a third embodiment of the present invention. Fig. 11 to 14 show a state in which the valve shaft 50A is inserted into the bearing portion 45 of the drive portion case 42, a state in which the valve body 10 and the drive portion case 42 are irradiated with infrared rays, a state in which the valve body 10 and the drive portion case 42 are joined (a state in which a welded portion is in contact before welding), and a state in which the valve body 10 and the drive portion case 42 are joined (a welded state) in this order.

The valve body 10 is provided with a valve body side welded portion 16 a. The valve main body side fusion-bonded portion 16a is an annular projection formed to project upward from the upper end of the peripheral wall portion 16.

An annular tapered surface 24a is provided on the peripheral edge of the valve shaft insertion hole 24 in the ball valve body 20. Further, an annular tapered surface 52c is provided on the peripheral edge of a valve body side stopper surface 52b which is the lower surface (end surface on the ball valve body 20 side) of the valve shaft 50. Thus, even when the axes of the valve shaft 50 are shifted from each other when the valve shaft 50 is inserted into the valve shaft insertion hole 24, the valve shaft 50 can be guided to the valve shaft insertion hole 24 by the tapered surfaces 24a and 52c, and the valve shaft 50 and the valve shaft insertion hole 24 can be automatically aligned with each other. Only one of the tapered surfaces 24a and 52c may be provided.

The lower case 43 is provided with a case-side welded portion 43 c. The case-side fusion-bonded portion 43c is an annular projection formed to project downward from the bottom wall 43 a. The case-side fusion-bonded portion 43c is disposed so as to surround the rib 43 b. The case-side welded portion 43c has the same shape as the valve body-side welded portion 16a in a plan view. An annular tapered surface 43d is provided on the outer edge of the lower end surface of the rib 43 b. Even when the rib 43b is inserted into the inner side of the peripheral wall portion 16 of the valve body 10, the tapered surface 43d abuts against the peripheral wall portion 16, and the rib 43b can be guided to the inner side of the peripheral wall portion 16.

Next, an example of a method for manufacturing the flow path switching valve 3 according to the present embodiment will be described with reference to fig. 11 to 14.

As shown in fig. 11, the ball valve body 20 is housed in the valve chamber 14 of the valve body 10. Further, the cylindrical portion 51 of the valve shaft 50A is inserted into the bearing portion 45 provided in the lower housing 43 of the drive portion housing 42. In this state, the closing member 54 closes the gap between the valve shaft 50A and the bearing 45.

Next, as shown in fig. 12, the valve body 10 is joined to the lower case 43 of the drive unit case 42 in the middle. Specifically, the rib 43b is inserted into the inside of the peripheral wall portion 16 of the valve main body 10 in the vertical direction, and the inner peripheral surface of the peripheral wall portion 16 is disposed in contact with the outer peripheral surface of the rib 43 b. At this time, the valve body side welded portion 16a and the case side welded portion 43c face each other with a gap therebetween in the vertical direction. In this state, the valve body side fusion-bonded portion 16a and the case side fusion-bonded portion 43c are irradiated with infrared rays and fused. In the state shown in fig. 12, the valve shaft 50 is not yet inserted into the valve shaft insertion hole 24, but the valve shaft 50 may be inserted into the valve shaft insertion hole 24. The irradiation with infrared rays may be performed in the state shown in fig. 11.

Next, as shown in fig. 13 and 14, the valve body 10 is completely coupled to the lower case 43 of the drive unit case 42. Specifically, as shown in fig. 13, the rib 43b is continuously inserted into the peripheral wall portion 16 of the valve main body 10, and the valve main body side welded portion 16a and the case side welded portion 43c are brought into contact with each other. Then, as shown in fig. 14, the above insertion is further performed, and the valve body side fusion-bonded portion 16a and the case side fusion-bonded portion 43c are fused to each other. At the same time, the valve shaft 50 is inserted into the valve shaft insertion hole 24.

The distance between the valve main body 10 and the lower case 43 in a state where the valve main body side fusion-bonded portion 16a and the case side fusion-bonded portion 43C are in contact with each other (in the contact state in fig. 13) is denoted by C. The distance between the valve body 10 and the lower case 43 in the state where the valve body side welded portion 16a and the case side welded portion 43c are welded (fig. 14, welded state) is D. The value obtained by subtracting the distance D from the distance C is the distance (referred to as "welding amount") by which the valve body 10 and the lower housing 43 approach each other by welding. The welding amount is preferably about 0.3mm to 1.0 mm.

In the abutting state shown in fig. 13, the length E in the vertical direction of the contact portion between the inner peripheral surface of the peripheral wall portion 16 and the outer peripheral surface of the rib 43b is preferably 1.5mm or more. As described above, the inner peripheral surface of the peripheral wall portion 16 contacts the outer peripheral surface of the rib 43b, whereby the lower case 43 is guided to move in the vertical direction, and movement in the direction orthogonal to the vertical direction is restricted. This enables the lower case 43 to be joined to the valve main body 10 with high accuracy. Further, by setting the length E to 1.5mm or more, a sufficient portion can be secured where the inner peripheral surface of the peripheral wall portion 16 and the outer peripheral surface of the rib 43b are in contact with each other. Therefore, the welding of the drive unit case 42 and the valve main body 10 in a misaligned state can be more effectively suppressed.

Then, the gear 41 is press-fitted into the upper end portion of the columnar portion 51 of the valve shaft 50A, and the drive mechanism is assembled into the lower case 43 and the upper case 44 is closed, thereby completing the drive unit 40. In this manner, the flow path switching valve 3 is completed.

The flow path switching valve 3 of the present embodiment can also exhibit the same operational advantages as the flow path switching valve 1 of the first embodiment described above.

The flow path switching valve 3 may be attached in the same order as the flow path switching valve 2 of the second embodiment described above. That is, the prism portion 52 of the valve shaft 50A may be inserted into the valve shaft insertion hole 24 of the spherical valve body 20 housed in the valve chamber 14 until the valve body side stopper surface 52b abuts against the spherical valve body 20. Then, infrared welding is performed to join the valve main body 10 and the lower case 43 of the drive section case 42. Even when the infrared welding is adopted as described above, by disposing the closing member 54 outside the bearing portion 45, the valve shaft 50 and the closing member 54 can be prevented from falling off from the bearing portion 45 during the welding.

The embodiments of the present invention have been described above, but the present invention is not limited to these examples. A person skilled in the art can add, delete, design and modify the aforementioned embodiments as appropriate, and appropriately combine the features of the embodiments without departing from the spirit of the present invention, and the scope of the present invention is included in the embodiments.

Description of the symbols

1. 2, 3 … flow path switching valve, 10 … valve body, 10a … left side wall portion, 10b … front side wall portion, 10c … right side wall portion, 10d … back side wall portion, 11 … first flow path, 12 … second flow path, 13 … third flow path, 11a, 12a, 13a … opening, 14 … valve chamber, 15 … bottom wall portion, 16 … peripheral wall portion, 16a … valve body side fused portion, 20 … spherical valve core, 21 … first opening, 22 … second opening, 23 … third opening, 24 … valve shaft insertion hole, 24a … conical surface, 30 … supporting member, 31 … O ring, 40 … driving portion, 41 … gear, 42 … driving portion housing, 43 bearing portion lower housing, 43a 43 … bottom wall, 43b … rib, 43c … housing side fused portion, 43d … conical surface, 44 d … upper housing, … a …, … lower housing, … column …, … portion … groove …, … groove …, … groove, 53 … stopper, 52a, 53a … bearing side stopper surface, 52B, 53B … valve element side stopper surface, 52C … taper surface, 54 … closing member, M … weld, K … closing portion, a … distance from the closing portion to the lower end surface of the bearing portion, B … distance from the valve element side stopper surface to the ball valve element, C … distance between the valve body and the lower case in a state where the valve body side weld and the case side weld abut, D … distance between the valve body and the lower case in a state where the valve body side weld and the case side weld are welded, E … length in the vertical direction of the contact portion between the inner peripheral surface of the peripheral wall portion and the outer peripheral surface of the rib

Claims (8)

1. A flow path switching valve includes: a valve body made of resin, the valve body being provided with a valve chamber and a plurality of flow paths communicating with the valve chamber; a valve body which is housed in the valve chamber and is rotatable, and which switches the connection of the flow path according to a rotational position; a drive unit having a drive mechanism for rotating the valve body; and a valve shaft connecting the valve body and the drive mechanism, the flow path switching valve being characterized in that,

the drive unit has a resin drive unit case that houses the drive mechanism,

the drive portion housing is coupled to the valve body,

the drive section case is ultrasonically welded or infrared-welded to the valve main body,

the valve body has a valve shaft insertion hole into which the valve shaft is inserted,

the valve shaft insertion hole is formed to rotate the valve body in accordance with the rotation of the valve shaft,

the drive section housing integrally has a bearing section into which the valve shaft is inserted,

the valve shaft has an annular closing member that closes a gap between the valve shaft and the bearing portion,

the valve body is disposed such that the valve shaft insertion hole faces the bearing portion with a gap therebetween,

the valve shaft has a valve body side stopper surface which abuts the valve body when the valve shaft is inserted into the valve shaft insertion hole,

the flow path switching valve is configured such that a distance from a closing portion of the closing member to an end surface on a valve element side in the bearing portion is shorter than a distance from a stop surface on the valve element side to the valve element.

2. The flow path switching valve according to claim 1,

the valve shaft has a bearing-side stopper surface facing to a side opposite to the valve-body-side stopper surface, and the bearing-side stopper surface abuts against a valve-body-side end surface of the bearing portion when the valve shaft is inserted into the bearing portion.

3. The flow path switching valve according to claim 1 or 2,

an insertion portion of the valve shaft inserted into the valve shaft insertion hole is formed in a polygonal column shape,

the valve shaft insertion hole is formed in the same shape as the cross-sectional shape of the insertion portion.

4. The flow path switching valve according to claim 1 or 2,

the valve body has a peripheral wall portion,

the drive section case has an annular wall portion inserted inside the peripheral wall portion in a welding direction,

the flow path switching valve is configured such that an inner peripheral surface of the peripheral wall portion is in contact with an outer peripheral surface of the annular wall portion when the drive unit casing is welded to the valve main body.

5. The flow path switching valve according to claim 4,

the length of a contact portion between the inner peripheral surface of the peripheral wall portion and the outer peripheral surface of the annular wall portion in the welding direction is 1.5mm or more in a state before the drive portion case is welded to the valve main body.

6. The flow path switching valve according to claim 1 or 2,

an annular tapered surface is provided on at least one of a peripheral edge of the valve shaft insertion hole and a peripheral edge of an end surface of the valve shaft on the valve element side.

7. A method for manufacturing a flow path switching valve, the flow path switching valve comprising: a valve body made of resin, the valve body being provided with a valve chamber and a plurality of flow paths communicating with the valve chamber; a valve body which is housed in the valve chamber and is rotatable, and which switches the connection of the flow path according to a rotational position; a drive unit having a drive mechanism for rotating the valve body and a resin drive unit case for housing the drive mechanism; and a valve shaft connecting the valve body and the drive mechanism, wherein the flow path switching valve is manufactured by a method comprising the steps of,

the drive section housing integrally has a bearing section into which the valve shaft is inserted,

the valve shaft has an annular closing member that closes a gap between the valve shaft and the bearing portion,

the valve body has a valve shaft insertion hole into which the valve shaft is inserted so that the valve body rotates in accordance with rotation of the valve shaft,

the valve shaft has a valve body side stopper surface which abuts the valve body when the valve shaft is inserted into the valve shaft insertion hole,

the flow path switching valve is configured such that a distance from a closing portion of the closing member to a valve element side end surface in the bearing portion is shorter than a distance from the valve element side stopper surface to the valve element,

inserting the valve shaft into the valve shaft insertion hole of the valve body accommodated in the valve chamber until the valve body side stopper surface abuts against the valve body,

the valve body and the drive section housing are coupled so that the valve shaft insertion hole and the bearing section are opposed to each other with a space therebetween,

joining the drive portion case to the valve main body by ultrasonic welding or infrared welding in a state where the closing member is located outside the bearing portion,

after the drive section housing is welded to the valve main body, the valve shaft is moved in the axial direction toward the bearing section side so that the closing member closes the gap.

8. The method of manufacturing a flow path switching valve according to claim 7,

the valve body is joined to the drive portion case such that the length of the portion of the valve body in contact with the outer peripheral surface of the annular wall portion in the welding direction is 1.5mm or more, and then the drive portion case is ultrasonically welded or infrared-welded to the valve body.

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