Patent Description:
An example of an existing flow channel switching valve is disclosed in Patent Literature <NUM>. The flow channel switching valve includes a ball valve member that includes an elastic body that has an inlet path and an outlet path, and a valve case that has a valve chamber in which a ball valve member is rotatably installed, an entrance flow channel in communication with the valve chamber, and exit flow channels in communication with the valve chamber. In the flow channel switching valve, rotation of the ball valve member enables the entrance flow channel to selectively communicate with any one of the exit flow channels.

As for the flow channel switching valve in Patent Literature <NUM>, the ball valve member that includes the elastic body is directly supported by the valve case so as to be rotatable. As for another known flow channel switching valve, an annular resin seat member is interposed between a ball valve member and a valve case and rotatably supports the ball valve member. In the flow channel switching valve, the ball valve member is rotatably interposed between a pair of seat members, and the seat members are pressed against the ball valve member by interposing O-rings that are composed of, for example, a rubber material and that serve as sealing members between the seat members and the valve case in a compressed state to ensure sealing performance.

<CIT> discloses a laterally-assembled type three-way ball valve which comprises a valve body, three flanges connected to the side face of the valve body, and a ball body and a valve seat which are arranged in the valve body. The valve body is a sphere with the top face and the bottom face both cut into planes. The valve body, a gland and two of the three flanges are of an integrated structure, and the valve body and the third flange are of a split structure; or, a valve deck which is of a split structure together with the valve body is arranged on the side face of the valve body, and the valve body, the gland and the three flanges are of an integrated structure. Two valve seat bosses in an inner cavity of the valve body are provided, as well as the tool for assembling the three-way ball valve.

However, when the flow channel switching valve described above is assembled, it is necessary to interpose the ball valve member between the pair of the seat members and to push the sealing members in the compressed state into the valve chamber. Accordingly, it is difficult to insert these members into the valve chamber, and there is a problem with assembly precision, for example, the seat members are installed in the valve chamber with the seat members inclined.

In view of this, it is an object of the present invention to provide a flow channel switching valve that enables assembly precision to be effectively increased and a method for assembling the flow channel switching valve. Solution to Problem.

To achieve the above object, a flow channel switching valve according to the present invention comprises the features of one of claims <NUM> or <NUM>. A flow channel switching valve according to an aspect of the present invention includes a valve body that has a valve chamber and flow channels in communication with the valve chamber, a valve member that is installed in the valve chamber and that has a switching flow channel therein for switching between connections of the flow channels depending on a rotational position of the valve member, a pair of seat members that is installed in the valve chamber in an interval, that interposes the valve member therebetween, and that rotatably supports the valve member, a sealing member that is disposed between each seat member and the valve body, and a rotation driving section that causes the valve member to rotate about a rotation axis. The valve body is integrally provided with the flow channels. The valve body has an opening that is in communication with the valve chamber and that is used for inserting the valve member, the pair of seat members, and the sealing member during assembly. A size of the valve member in a direction of the rotation axis is smaller than a size thereof in a direction perpendicular to the rotation axis. A first jig mounting portion for rotating the valve member in the perpendicular direction is disposed on an inner wall surface of the valve member that is visible from a location outside the valve body through the opening or the flow channels.

In the present invention, a second jig mounting portion for rotating the valve member in the perpendicular direction may be disposed on the inner wall surface of the valve member that is visible from a location outside the valve body through the opening or the flow channels.

In the present invention, the size of the valve member in the direction of the rotation axis is smaller than the size thereof in the direction perpendicular to the rotation axis such that the sealing member is in a compressed state when the valve member has a support posture with the rotation axis being perpendicular to an opposing direction of the pair of seat members, and such that the sealing member is in a restoration state when the valve member has an assembly posture with the rotation axis being parallel to the opposing direction.

In the present invention, the jig mounting portion preferably has a recessed portion or a projecting portion that has a regular hexagonal shape.

According to one aspect of the present invention, the valve member has three valve member openings that face in the direction perpendicular to the rotation axis and that are connected to each other by using the switching flow channel, the three valve member openings are arranged about the rotation axis in an interval of <NUM> degrees, and diameters of two valve member openings opposite each other with the rotation axis interposed therebetween among the three valve member openings are smaller than a diameter of the other valve member opening.

According to another aspect of the present invention, the valve member has two valve member openings that face in the direction perpendicular to the rotation axis and that are connected to each other by using the switching flow channel, the two valve member openings are arranged about the rotation axis in an interval of <NUM> degrees, and a diameter of one valve member opening of the two valve member openings is smaller than a diameter of the other valve member opening.

To achieve the above object, a method for assembling a flow channel switching valve comprises the features of claims <NUM> or <NUM>. A method according to another aspect of the present invention is a method for assembling a flow channel switching valve that includes a valve body that has a valve chamber and flow channels in communication with the valve chamber, a valve member that is installed in the valve chamber and that has a switching flow channel therein for switching between connections of the flow channels depending on a rotational position of the valve member, a pair of seat members that is installed in the valve chamber in an interval, that interposes the valve member therebetween, and that rotatably supports the valve member, and a sealing member that is disposed between each seat member and the valve body, the valve body being integrally provided with the flow channels, and the valve body having an opening that is in communication with the valve chamber and that is used for inserting the valve member, the pair of seat members, and the sealing member during assembly, the pair of seat members rotatably supporting the valve member such that an assembly posture with a rotation axis of the valve member being parallel to an opposing direction of the pair of seat members changes into a support posture with the rotation axis being perpendicular to the opposing direction, the pair of seat members supporting the valve member that has the support posture such that the valve member is rotatable about the rotation axis, a size of the valve member in a direction of the rotation axis being smaller than a size thereof in a direction perpendicular to the rotation axis such that the seat members, the sealing member, or both are in a compressed state when the valve member has the support posture, and the seat members, the sealing member, or both are restored from the support posture when the valve member has the assembly posture, a first jig mounting portion that is configured such that the first jig mounting portion and a tip end portion of a rod-shaped jig fit together, and such that the valve member is rotated from the assembly posture into the support posture together with rotation of the rod-shaped jig being disposed on an inner wall surface of the valve member that is visible in a direction perpendicular to the opposing direction from a location outside the valve body through the opening or the flow channels when the valve member has the assembly posture. The method includes installing the pair of seat members and the sealing member in the valve chamber and disposing the valve member between the pair of seat members such that the valve member has the assembly posture, inserting the rod-shaped jig in the direction perpendicular to the opposing direction through the opening or the flow channels and fitting a tip end portion thereof and the first jig mounting portion together, and rotating the rod-shaped jig and rotating the valve member from the assembly posture into the support posture.

In the present invention, the pair of seat members may support the valve member that has the support posture such that the valve member is rotatable about a perpendicular axis parallel to the opposing direction, a second jig mounting portion that is configured such that the second jig mounting portion and the tip end portion of the rod-shaped jig fit together and such that the valve member is rotated about the perpendicular axis together with rotation of the rod-shaped jig may be disposed on the inner wall surface of the valve member that is visible in the opposing direction from a location outside the valve body through the opening or the flow channels when the valve member has the support posture, the rod-shaped jig may be inserted in the opposing direction through the flow channels, the tip end portion thereof and the second jig mounting portion may be fit together, the rod-shaped jig may be rotated, and the valve member may be rotated about the perpendicular axis. Advantageous Effects of Invention.

According to the present invention, the size of the valve member in the direction of the rotation axis is smaller than the size thereof in the direction perpendicular to the rotation axis. The first jig mounting portion for rotating the valve member in the perpendicular direction is disposed on the inner wall surface of the valve member that is visible from a location outside the valve body through the opening or the flow channels. This enables the interval between the pair of seat members to be increased in a manner in which the valve member is interposed between the pair of seat members in the direction of the rotation axis, the valve member, the pair of seat members, and the sealing member are installed in the valve chamber through the opening of the valve body, and the valve member is subsequently rotated in the perpendicular direction by using the first jig mounting portion. For this reason, assembly can be more accurate than the case where the valve member is interposed between the pair of seat members in the direction perpendicular to the rotation axis.

In addition, according to the present invention, the pair of seat members and the sealing member are installed in the valve chamber, and the valve member is disposed between the pair of seat members such that the valve member has the assembly posture, during the assembly of the flow channel switching valve. The rod-shaped jig is inserted in the direction perpendicular to the opposing direction through the opening or the flow channels of the valve body, the tip end portion thereof and the first jig mounting portion are fit together. The rod-shaped jig is rotated, and the valve member is rotated from the assembly posture into the support posture. This enables the seat members and the sealing member to be in the compressed state in a manner in which the valve member, the pair of seat members, and the sealing member are installed in the valve chamber in a state in which the degree of compression of the sealing member is relatively low, and the valve member is subsequently rotated from the assembly posture into the support posture by using the rod-shaped jig. For this reason, the assembly can be more accurate than the case where the sealing member in the compressed state is pushed into the valve chamber.

In addition, since the first jig mounting portion is disposed on the inner wall surface of the valve member, the jig mounting portion and the seat members do not interfere with each other. For this reason, a jig mounting portion that has a projecting shape, for example, can be used, and the degree of freedom of the structure of the jig mounting portion is higher than that of a structure in which the jig mounting portion is disposed on an outer surface of the valve member. Furthermore, even when foreign substances accumulate on a jig mounting portion that has a recessed shape, the foreign substances do not come into contact with the seat members, and the seat members can be inhibited from being damaged due to the foreign substances.

The structure of a flow channel switching valve according to a first embodiment of the present invention will now be described with reference to <FIG>.

<FIG> illustrates a front view of the flow channel switching valve according to the first embodiment of the present invention. <FIG> illustrates a cross-sectional view (a vertical cross-sectional view) of the flow channel switching valve in <FIG> taken along a rotation axis. <FIG> is a cross-sectional view taken along line A-A in <FIG>. <FIG> illustrates a perspective view containing a section of the flow channel switching valve in <FIG>. <FIG> illustrates a view of six sides of a ball valve member that the flow channel switching valve in <FIG> includes. In the following description, the terms "upper, lower, left, and right" are used to represent relative positional relationships of components in the figures and do not represent absolute positional relationships. In the drawings, an X-axis direction represents a left-and-right direction, a Y-axis direction represents a front-and-rear direction, and a Z-axis direction represents an up-and-down direction. An X-axis, a Y-axis, a Z-axis are perpendicular to each other.

As illustrated in <FIG>, a flow channel switching valve <NUM> according to the present embodiment includes a valve body <NUM>, a ball valve member <NUM>, a pair of seat members <NUM>, sealing members <NUM>, a driving section <NUM> that serves as a rotation driving section, and a valve shaft <NUM>.

The valve body <NUM> is composed of synthetic resin and has a substantially cubic box shape. A first flow channel <NUM> that has a substantially L-shape is provided on a left side wall portion 10a of the valve body <NUM>. A second flow channel <NUM> that is linear is provided on a front wall portion 10b of the valve body <NUM>. A third flow channel <NUM> that has a substantially L-shape is provided on a right side wall portion 10c of the valve body <NUM>. An opening 11a in the first flow channel <NUM>, an opening 12a in the second flow channel <NUM>, and an opening 13a in the third flow channel <NUM> face in the same direction (a front direction, or a forward direction from the paper in <FIG>). The first flow channel <NUM>, the second flow channel <NUM>, and the third flow channel <NUM> are in communication with a valve chamber <NUM> that is provided in the valve body <NUM>. Two flow channels or four or more flow channels in communication with the valve chamber <NUM> may be provided. In the present embodiment, the second flow channel <NUM> extends in the Y-axis direction. The valve body <NUM> has an opening 10e in communication with the valve chamber <NUM>. The opening 10e faces upward.

The seat members <NUM> are composed of, for example, synthetic resin such as polytetrafluoroethylene (PTFE) and have an annular shape. The seat members <NUM> may be composed of an elastic material such as a rubber material. The seat members <NUM> are paired with each other and are installed in the valve chamber <NUM> so as to face each other in an interval in the X-axis direction. The X-axis direction coincides with an opposing direction of the seat members <NUM> (also referred to below as an "opposing direction X"). The seat members <NUM> interpose and rotatably support the ball valve member <NUM> that will be described later in the valve chamber <NUM>.

Specifically, the seat members <NUM> rotatably support the ball valve member <NUM> such that an assembly posture (<FIG>) with an axis L that represents the rotation axis of the ball valve member <NUM> being parallel to the opposing direction X changes into a support posture (<FIG>) with the axis L being parallel to the Z-axis direction perpendicular to the opposing direction X during the assembly of the flow channel switching valve <NUM>. The seat members <NUM> also support the ball valve member <NUM> that has the support posture such that the ball valve member <NUM> is rotatable about the axis L (the Z-axis) at the time of completion of the assembly of the flow channel switching valve <NUM> (that is, a completion state in which the flow channel switching valve can operate). The structure of each seat member <NUM> is freely determined provided that the ball valve member <NUM> is interposed therebetween and is rotatably supported unless it goes against the purpose of the present invention.

The sealing members <NUM> are, for example, O-rings composed of an elastic material such as a rubber material, one of which is interposed between one of the seat members <NUM> and the left side wall portion 10a of the valve body <NUM> so as to be in a compressed state, and the other of which is interposed between the other seat member <NUM> and the right side wall portion 10c of the valve body <NUM> so as to be in the compressed state. In the present embodiment, the sealing members <NUM> are fitted in annular grooves 30a that the seat members <NUM> have and partly project from the annular grooves 30a. The sealing members <NUM> seal a space between the valve body <NUM> and the ball valve member <NUM> together with the seat members <NUM>. It is a matter of course that members obtained by integrating the seat members <NUM> and the sealing members <NUM> may be used.

The ball valve member <NUM> is composed of, for example, a material such as metal or synthetic resin and has a hollow ball-like shape (a spherical shape). The ball valve member <NUM> is rotatably supported by the seat members <NUM> and is installed in the valve chamber <NUM>. The ball valve member <NUM> has a first opening <NUM> that opens in the left-hand direction, a second opening <NUM> that opens in the front direction (downward in <FIG>), and a third opening <NUM> that opens in the right-hand direction when being located at a rotational position illustrated in <FIG>. A switching flow channel <NUM> that has a substantially T-shape in a plan view and that connects the first opening <NUM>, the second opening <NUM>, and the third opening <NUM> to each other is provided in the ball valve member <NUM>. For example, the ball valve member <NUM> may have only the first opening <NUM> and the second opening <NUM>, and the switching flow channel <NUM> may have a substantially L-shape in a plan view and may connect the first opening <NUM> and the second opening <NUM> to each other. In the present embodiment, the ball valve member <NUM> is used as the valve member, but a columnar valve member may be used.

The first opening <NUM>, the second opening <NUM>, and the third opening <NUM> in the ball valve member <NUM> are three valve member openings that face in the direction perpendicular to the axis L and are connected to each other by using the switching flow channel <NUM>. The first opening <NUM>, the second opening <NUM>, and the third opening <NUM> are arranged about the axis L in an interval of <NUM> degrees. For example, when the second opening <NUM> faces in the Y-axis direction, the first opening <NUM> and the third opening <NUM> face in opposite directions parallel to the X-axis direction. In the present embodiment, the first opening <NUM>, the second opening <NUM>, and the third opening <NUM> have a circular shape (including a substantially circular shape) and have the same diameter.

The switching flow channel <NUM> is formed such that connections among the first flow channel <NUM>, the second flow channel <NUM>, and the third flow channel <NUM> are switched depending on the rotational position of the ball valve member <NUM>. Specifically, the switching flow channel <NUM> connects the first flow channel <NUM>, the second flow channel <NUM>, and the third flow channel <NUM> to each other when the ball valve member <NUM> is located at the rotational position illustrated in <FIG>. The switching flow channel <NUM> connects the first flow channel <NUM> and the second flow channel <NUM> to each other when the ball valve member <NUM> is located at the rotational position at which the ball valve member <NUM> is rotated <NUM> degrees clockwise in a plan view from the rotational position illustrated in <FIG>. The switching flow channel <NUM> connects the second flow channel <NUM> and the third flow channel <NUM> to each other when the ball valve member <NUM> is located at the rotational position at which the ball valve member <NUM> is rotated <NUM> degrees counterclockwise in a plan view from the rotational position illustrated in <FIG>.

A valve shaft insertion hole <NUM> in which the valve shaft <NUM> described later is inserted is provided in an upper portion of the ball valve member <NUM>. The valve shaft insertion hole <NUM> is formed such that the ball valve member <NUM> is rotated about the axis L together with rotation of the valve shaft <NUM> with the valve shaft <NUM> inserted therein. Specifically, the valve shaft insertion hole <NUM> has the same shape as a cross-sectional shape (a transverse cross-sectional shape) of a prism portion <NUM> of the valve shaft <NUM> in the direction perpendicular to the rotation axis. In the present embodiment, the valve shaft insertion hole <NUM> has a regular hexagonal shape.

The size H of the ball valve member <NUM> in the direction of the axis L is smaller than the size W thereof in the direction perpendicular to the axis L (H < W) such that the sealing members <NUM> are in a restoration state (a state in which no force is applied from the outside, and there is no elastic deformation) when the ball valve member <NUM> has the assembly posture (<FIG>) with the axis L being parallel to the X-axis direction (the opposing direction X), and such that the sealing members <NUM> are in the compressed state when the ball valve member <NUM> has the support posture (<FIG>) with the axis L being parallel to the Z-axis direction (the direction perpendicular to the opposing direction X). In this case, when the ball valve member <NUM> has the assembly posture in the valve chamber <NUM>, the sealing members <NUM> are in the restoration state. Accordingly, the ball valve member <NUM>, the seat members <NUM>, and the sealing members <NUM> can be inserted into the valve chamber <NUM> without press-fitting. When the ball valve member <NUM> has the support posture in the valve chamber <NUM>, the sealing members <NUM> are in the compressed state. Accordingly, the seat members <NUM> are pressed against the ball valve member <NUM>, and the space between the ball valve member <NUM> and the valve body <NUM> is sealed. It is only necessary for the size H of the ball valve member <NUM> in the direction of the axis L to be smaller than the size W thereof in the direction perpendicular to the axis such that the sealing members <NUM> are in the compressed state when the ball valve member <NUM> has the support posture, and such that the sealing members <NUM> are restored from the support posture when the ball valve member <NUM> has the assembly posture.

A jig mounting portion <NUM> is disposed on an inner wall surface <NUM> of the ball valve member <NUM> opposite the second opening <NUM>. The jig mounting portion <NUM> has a projecting shape of a substantially regular hexagonal prism that projects toward the second opening <NUM>, and a recessed portion 27a that has a regular hexagonal shape is disposed on a tip end surface. In the present embodiment, the recessed portion 27a is configured such that the recessed portion 27a and a tip end portion of a hexagonal wrench that serves as a rod-shaped jig fit together. The recessed portion 27a may be configured such that the recessed portion 27a and a tip end portion of a cross-head screwdriver or a flat head screwdriver that serves as the rod-shaped jig fit together. The jig mounting portion <NUM> may be configured to be a projecting portion that is fitted in a socket wrench. The cost of the rod-shaped jig can be decreased by matching the shape of the jig mounting portion <NUM> to the shape of, for example, a commercially available hexagonal wrench. The jig mounting portion <NUM> corresponds to a first jig mounting portion.

When the ball valve member <NUM> is disposed in the valve chamber <NUM> so as to have the assembly posture, the second flow channel <NUM>, the second opening <NUM>, and the inner wall surface <NUM> can be linearly aligned. In the case of the assembly posture, the jig mounting portion <NUM> on the inner wall surface <NUM> is visible in the Y-axis direction perpendicular to the opposing direction X from a location outside the valve body <NUM> through the second flow channel <NUM> and the switching flow channel <NUM>.

The driving section <NUM> includes a driving mechanism that includes a combination of a motor, not illustrated, and a speed reducer that includes a gear <NUM>, and a driving section case <NUM> composed of resin in which the driving mechanism is installed. The driving section case <NUM> has a substantially rectangular parallelepiped box shape. The driving section case <NUM> includes a lower case <NUM> and an upper case <NUM>. The lower case <NUM> and the upper case <NUM> are assembled by using an attachment structure, not illustrated, such as a screw structure or a snap-fit structure.

The lower case <NUM> includes a cylindrical bearing portion <NUM> that is integrated therewith at the center of a bottom wall 43a. The valve shaft <NUM> is inserted in the bearing portion <NUM>, and the bearing portion <NUM> rotatably supports the valve shaft <NUM>. A rib 43b that is disposed on the bottom wall 43a of the lower case <NUM> is assembled with an upper end portion of the valve body <NUM> (a valve body <NUM> in a second embodiment described later), and these are joined to each other at a weld portion M (by ultrasonic welding in the present embodiment). The lower case <NUM> and the valve body <NUM> may be assembled with each other by using a screw structure or the like.

The valve shaft <NUM> has a columnar shape that linearly extends overall and includes a round columnar portion <NUM> and the prism portion <NUM> that is coaxially connected to the lower end of the round columnar portion <NUM>. The valve shaft <NUM> extends in the Z-axis direction.

A stopper portion <NUM> that extends outward in the radial direction and that has an annular shape is disposed on a lower end portion of the round columnar portion <NUM>. The outer diameter of the stopper portion <NUM> is larger than the outer diameter of the round columnar portion <NUM> and the inner diameter of the bearing portion <NUM>.

A groove is provided on the lower end portion of the round columnar portion <NUM> over the entire circumference at a position higher than the stopper portion <NUM>, and an O-ring <NUM> that is composed of, for example, a rubber material and that as an annular shape is fitted in the groove. The round columnar portion <NUM> is inserted in the bearing portion <NUM> and is rotatably supported by the bearing portion <NUM>. The outer diameter of the round columnar portion <NUM> is slightly smaller than the inner diameter of the bearing portion <NUM>, and the O-ring <NUM> seals a gap between the valve shaft <NUM> and the bearing portion <NUM> when the round columnar portion <NUM> is inserted in the bearing portion <NUM>. This prevents a fluid in the valve chamber <NUM> from leaking to the outside.

The gear <NUM> of the drive portion <NUM> is secured to and mounted on an upper end portion of the round columnar portion <NUM> by press-fitting, and the valve shaft <NUM> is rotated together with rotation of the gear <NUM>. A flat portion that inhibits the press-fitted gear <NUM> from slipping is disposed on the upper end portion of the round columnar portion <NUM>.

The prism portion <NUM> has a columnar shape a transverse cross-sectional shape of which is a regular hexagonal shape. The prism portion <NUM> is inserted in the valve shaft insertion hole <NUM> of the ball valve member <NUM>. In this state, the rotation axis of the valve shaft <NUM> coincides with the axis L of the ball valve member <NUM>. The valve shaft insertion hole <NUM> has a regular hexagonal shape a transverse cross-sectional shape of which is the same as that of the prism portion <NUM>. For this reason, the valve shaft insertion hole <NUM> and the prism portion <NUM> fit together, and the ball valve member <NUM> is rotated about the axis L together with rotation of the valve shaft <NUM>. The outer diameter of the prism portion <NUM> is smaller than that of the stopper portion <NUM>.

The prism portion <NUM> may have a polygonal columnar shape such as a triangular prism shape or a quadrangular prism shape, or a columnar having a D-shaped cross-section having a plane on a part of the circumferential surface, in addition to a regular hexagonal shape. In this case, the valve shaft insertion hole <NUM> has the same shape as the transverse cross-sectional shape of the prism portion <NUM>.

As for the flow channel switching valve <NUM>, rotation of the motor of the driving section <NUM> is transmitted to the valve shaft <NUM> via the gear <NUM>, and the valve shaft <NUM> is rotated. The ball valve member <NUM> is rotated about the axis L parallel to the Z-axis direction together with rotation of the valve shaft <NUM> and moves to each of the rotational positions. This achieves connections of the flow channels depending each of the rotational positions.

An example of a method for assembling the flow channel switching valve <NUM> according to the present embodiment will now be described with reference to <FIG>.

<FIG> illustrate the method for assembling the flow channel switching valve in <FIG>. Specifically, <FIG> is an exploded perspective view illustrating a state before the ball valve member <NUM>, the seat members <NUM>, and the sealing members <NUM> are inserted into the valve body <NUM>. <FIG> illustrates a state in which the ball valve member <NUM>, the seat members <NUM>, and the sealing members <NUM> are inserted in the valve body <NUM>, and the ball valve member <NUM> has the assembly posture with the axis L being parallel to the X-axis direction. <FIG> illustrates a state in which the ball valve member <NUM> is rotated from the assembly posture with the axis L being parallel to the X-axis direction into the support posture with the axis L being parallel to the Z-axis direction in the valve chamber <NUM>. <FIG> is an exploded perspective view illustrating a state before the driving section is joined to the valve body <NUM>. In <FIG> and <FIG>, perspective views each containing a section are illustrated at (a), and enlarged vertical cross-sectional views are illustrated at (b).

As illustrated in <FIG>, the ball valve member <NUM> is first disposed such that the axis L is parallel to the X-axis direction, and the second opening <NUM> faces in the front direction. The ball valve member <NUM> is interposed between the seat members <NUM> in the X-axis direction (the opposing direction X). The sealing members <NUM> are fitted into the annular grooves 30a of the seat members <NUM>. As illustrated in <FIG>, the ball valve member <NUM>, the seat members <NUM>, and the sealing members <NUM> are inserted into the valve chamber <NUM> through the opening 10e of the valve body <NUM> with these being in contact with each other. At this time, the ball valve member <NUM> has the assembly posture with the axis L being parallel to the opposing direction X, and the sealing members <NUM> are in the restoration state in the valve chamber <NUM>. For this reason, the sealing members <NUM> do not elastically deform, and the ball valve member <NUM>, the seat members <NUM>, and the sealing members <NUM> can be smoothly installed in the valve chamber <NUM>. The second flow channel <NUM>, the second opening <NUM>, and the inner wall surface <NUM> are linearly arranged in the Y-axis direction, and the jig mounting portion <NUM> is visible in the Y-axis direction from a location outside the valve body <NUM> through the second flow channel <NUM> and the switching flow channel <NUM>.

Subsequently, the hexagonal wrench, not illustrated, which serves as the rod-shaped jig, is inserted in the Y-axis direction into the second opening <NUM> through the second flow channel <NUM> in a state illustrated in <FIG>, and the tip end portion thereof and the recessed portion 27a of the jig mounting portion <NUM> are fit together. The ball valve member <NUM> is rotated in the direction (about the Y-axis direction) perpendicular to the axis L by rotating the hexagonal wrench in the counterclockwise direction illustrated by an arrow in <FIG>. As illustrated in <FIG>, the axis L of the ball valve member <NUM> is matched to the Z-axis direction, and the posture becomes the support posture. In this case, since the size W of the ball valve member <NUM> in the direction perpendicular to the direction of the axis L is larger than the size H thereof in the direction of the axis L (H < W), when the assembly posture of the ball valve member <NUM> changes into the support posture, the interval between the seat members <NUM> widens, and the state of the sealing members <NUM> changes from the restoration state into the compressed state. The seat members <NUM> support the ball valve member <NUM> that has the support posture such that the ball valve member <NUM> is rotatable about the axis L parallel to the Z-axis direction. In the present description, to rotate in the direction perpendicular to the axis L means to rotate about a straight line parallel to the direction perpendicular to the axis L with the straight line coinciding with the rotation axis.

Subsequently, the prism portion <NUM> of the valve shaft <NUM> is inserted into the valve shaft insertion hole <NUM> of the ball valve member <NUM> that has the support posture and that is installed in the valve chamber <NUM>, the round columnar portion <NUM> of the valve shaft <NUM> is inserted into the bearing portion <NUM>, and the valve body <NUM> and the lower case <NUM> of the driving section case <NUM> are combined. The lower case <NUM> is exposed to ultrasonic, and the lower case <NUM> is welded to the valve body <NUM> by ultrasonic welding. The driving mechanism is incorporated with the lower case <NUM>, for example, by press-fitting the gear <NUM> to the round columnar portion <NUM> of the valve shaft <NUM> and is covered with the upper case <NUM>, the driving section <NUM> is assembled, and the flow channel switching valve <NUM> is completed.

As for the flow channel switching valve <NUM> according to the present embodiment described above, the seat members <NUM> and the sealing members <NUM> are installed in the valve chamber <NUM> during the assembly of the flow channel switching valve <NUM>, and the ball valve member <NUM> is disposed between the seat members <NUM> so as to have the assembly posture. The rod-shaped jig is inserted in the Y-axis direction perpendicular to the opposing direction X through the second flow channel <NUM> of the valve body <NUM>, and the tip end portion thereof and the recessed portion 27a of the jig mounting portion <NUM> are fit together. The rod-shaped jig is rotated, and the ball valve member <NUM> is rotated from the assembly posture into the support posture. In this way, the state of the sealing members <NUM> can be changed from the restoration state into the compressed state in a manner in which the ball valve member <NUM>, the seat members <NUM>, and the sealing members <NUM> are installed in the valve chamber <NUM> with the sealing members <NUM> being in the restoration state, and the ball valve member <NUM> is subsequently rotated from the assembly posture into the support posture by using the rod-shaped jig. For this reason, the assembly is more accurate than the case where the sealing members <NUM> in the compressed state are pushed into the valve chamber.

In addition, since the jig mounting portion <NUM> is disposed on the inner wall surface <NUM> of the ball valve member <NUM>, the jig mounting portion <NUM> and the seat members <NUM> do not interfere with each other. For this reason, the jig mounting portion <NUM> that has a projecting shape can be used, and the degree of freedom of the structure of the jig mounting portion <NUM> is higher than that of a structure in which the jig mounting portion <NUM> is disposed on an outer surface of the ball valve member <NUM>. Furthermore, even when foreign substances accumulate on the recessed portion 27a of the jig mounting portion <NUM>, the foreign substances do not come into contact with the seat members <NUM>, and the seat members <NUM> can be inhibited from being damaged due to the foreign substances.

The structure of a flow channel switching valve according to a second embodiment of the present invention will now be described with reference to <FIG>.

<FIG> illustrates a front view of the flow channel switching valve according to the second embodiment of the present invention. <FIG> illustrates a cross-sectional view (a vertical cross-sectional view) of the flow channel switching valve in <FIG> taken along the rotation axis. <FIG> illustrates a cross-sectional view taken along line B-B in <FIG>. <FIG> illustrates a perspective view containing a section of the flow channel switching valve in <FIG>. <FIG> illustrates a view of six sides of a ball valve member that the flow channel switching valve in <FIG> includes. In the following description, the terms "upper, lower, left, and right" are used to represent relative positional relationships of components in the figures and do not represent absolute positional relationships. In the drawings, the X-axis direction represents the left-and-right direction, the Y-axis direction represents the front-and-rear direction, and the Z-axis direction represents the up-and-down direction. The X-axis, the Y-axis, the Z-axis are perpendicular to each other.

As illustrated in <FIG>, a flow channel switching valve <NUM> according to the present embodiment includes the valve body <NUM>, a ball valve member <NUM>, the pair of the seat members <NUM>, the sealing members <NUM>, the driving section <NUM>, and the valve shaft <NUM>. In the following description, the same components as those described in the first embodiment described above are denoted by corresponding ones of the reference signs used in the first embodiment, and description of such components is omitted.

The valve body <NUM> is composed of synthetic resin and has a substantially cubic box shape. A first flow channel <NUM> that linearly extends in the left-hand direction is provided on a left side wall portion 110a of the valve body <NUM>. A second flow channel <NUM> that linearly extends downward is provided on a bottom wall portion 110d of the valve body <NUM>. A third flow channel <NUM> that linearly extends in the right-hand direction is provided on a right side wall portion 110c of the valve body <NUM>. An opening 111a in the first flow channel <NUM> faces in the left-hand direction, an opening 112a in the second flow channel <NUM> faces downward, and an opening 113a in the third flow channel <NUM> faces in the right-hand direction. The first flow channel <NUM>, the second flow channel <NUM>, and the third flow channel <NUM> are in communication with a valve chamber <NUM> that is provided in the valve body <NUM>. Two flow channels or four or more flow channels in communication with the valve chamber <NUM> may be provided. The valve body <NUM> has an opening 110e in communication with the valve chamber <NUM>. The opening 110e faces upward.

In the present embodiment, the seat members <NUM> are paired with each other and are installed in the valve chamber <NUM> so as to face each other in an interval in the X-axis direction. The seat members <NUM> rotatably support the ball valve member <NUM> such that the assembly posture (<FIG>) with the axis L of the ball valve member <NUM> being parallel to the opposing direction X changes into the support posture (<FIG>) with the axis L being parallel to the Y-axis direction perpendicular to the opposing direction X during the assembly of the flow channel switching valve <NUM>. The seat members <NUM> also support the ball valve member <NUM> that has the support posture such that the ball valve member <NUM> is rotatable about a perpendicular axis K parallel to the opposing direction X. The seat members <NUM> also support the ball valve member <NUM> that has the support posture with the axis L being parallel to the Z-axis direction such that the ball valve member <NUM> is rotatable about the axis L (the Z-axis) at the time of completion of the assembly of the flow channel switching valve <NUM>. The structure of each seat member <NUM> is freely determined provided that the ball valve member <NUM> is interposed therebetween and is rotatably supported unless it goes against the purpose of the present invention.

In the present embodiment, one of the sealing members <NUM> is interposed between one of the seat members <NUM> and the left side wall portion 110a of the valve body <NUM> so as to be in the compressed state, and the other is interposed between the other seat member <NUM> and the right side wall portion 110c of the valve body so as to be in the compressed state. The sealing members <NUM> are fitted in the annular grooves 30a that the seat members <NUM> have and partly project from the annular grooves 30a. The sealing members <NUM> seal a space between the valve body <NUM> and the ball valve member <NUM> together with the seat members <NUM>.

The ball valve member <NUM> is composed of, for example, a material such as metal or synthetic resin and has a hollow ball-like shape (a spherical shape). The ball valve member <NUM> is rotatably supported by the seat members <NUM> and is installed in the valve chamber <NUM>. The ball valve member <NUM> has a first opening <NUM> that opens downward (a backward direction from the paper in <FIG>), a second opening <NUM> that opens in the front direction (downward in <FIG>), and a third opening <NUM> that opens in the right-hand direction (the right-hand direction in <FIG>) when being located at the rotational position illustrated in <FIG>. A switching flow channel <NUM> that connects the first opening <NUM>, the second opening <NUM>, and the third opening <NUM> to each other is provided in the ball valve member <NUM>.

The switching flow channel <NUM> is formed such that connections among the first flow channel <NUM>, the second flow channel <NUM>, and the third flow channel <NUM> are switched depending on the rotational position. Specifically, the switching flow channel <NUM> connects the first flow channel <NUM> and the third flow channel <NUM> to each other when the ball valve member <NUM> is located at the rotational position illustrated in <FIG>. The switching flow channel <NUM> connects the first flow channel <NUM> and the second flow channel <NUM> to each other when the ball valve member <NUM> is located at the rotational position at which the ball valve member <NUM> is rotated <NUM> degrees clockwise in a plan view from the rotational position illustrated in <FIG>.

A valve shaft insertion hole <NUM> in which the valve shaft <NUM> is inserted is provided in an upper portion of the ball valve member <NUM>. The valve shaft insertion hole <NUM> is formed such that the ball valve member <NUM> is rotated about the axis L together with rotation of the valve shaft <NUM> with the valve shaft <NUM> inserted therein. Specifically, the valve shaft insertion hole <NUM> has the same shape as a cross-sectional shape (a transverse cross-sectional shape) of the prism portion <NUM> of the valve shaft <NUM> in the direction perpendicular to the rotation axis. In the present embodiment, the valve shaft insertion hole <NUM> has a regular hexagonal shape.

The size H of the ball valve member <NUM> in the direction of the axis L is smaller than the size W thereof in the direction perpendicular to the axis L (H < W) such that the sealing members <NUM> are in the restoration state when the ball valve member <NUM> has the assembly posture illustrated in <FIG>, and such that the sealing members <NUM> are in the compressed state when the ball valve member <NUM> has the support posture illustrated in <FIG> and <FIG>. In this case, when the ball valve member <NUM> has the assembly posture in the valve chamber <NUM>, the sealing members <NUM> are in the restoration state. Accordingly, the ball valve member <NUM>, the seat members <NUM>, and the sealing members <NUM> can be inserted into the valve chamber <NUM> without press-fitting. When the ball valve member <NUM> has the support posture in the valve chamber <NUM>, the sealing members <NUM> are in the compressed state. Accordingly, the seat members <NUM> are pressed against the ball valve member <NUM>, and the space between the ball valve member <NUM> and the valve body <NUM> is sealed. It is only necessary for the size H of the ball valve member <NUM> in the direction of the axis L to be smaller than the size W thereof in the direction perpendicular to the axis such that the sealing members <NUM> are in the compressed state when the ball valve member <NUM> has the support posture, and such that the sealing members <NUM> are restored from the support posture when the ball valve member <NUM> has the assembly posture.

A first jig mounting portion <NUM> is disposed on an inner wall surface <NUM> of the ball valve member <NUM> opposite the second opening <NUM>. The first jig mounting portion <NUM> has a projecting shape of a substantially regular hexagonal prism that projects toward the second opening <NUM>, and a recessed portion 127a that has a regular hexagonal shape is disposed on a tip end surface. In the present embodiment, the recessed portion 127a is configured such that the recessed portion 127a and the tip end portion of the hexagonal wrench that serves as the rod-shaped jig fit together. The recessed portion 127a may be configured such that the recessed portion 127a and the tip end portion of the cross-head screwdriver or the flat head screwdriver that serves as the rod-shaped jig fit together. The first jig mounting portion <NUM> may be configured to be a projecting portion that is fitted in the socket wrench. The cost of the rod-shaped jig can be decreased by matching the shape of the first jig mounting portion <NUM> to the shape of, for example, a commercially available hexagonal wrench.

A second jig mounting portion <NUM> is disposed on an inner wall surface <NUM> of the ball valve member <NUM> opposite the third opening <NUM>. The second jig mounting portion <NUM> has a projecting shape of a substantially regular hexagonal prism that projects toward the third opening <NUM>, and a recessed portion 129a that has a regular hexagonal shape is disposed on a tip end surface. In the present embodiment, the recessed portion 129a and the tip end portion of the hexagonal wrench that serves as the rod-shaped jig fit together as in the recessed portion 129a of the first jig mounting portion <NUM>.

When the ball valve member <NUM> is disposed in the valve chamber <NUM> so as to have the assembly posture, the second opening <NUM> can face upward, and the third opening <NUM> can face in the front direction. In the case of the assembly posture, the first jig mounting portion <NUM> on the inner wall surface <NUM> is visible in the Z-axis direction perpendicular to the opposing direction X from a location outside the valve body <NUM> through the opening 110e. When the ball valve member <NUM> is rotated such that the assembly posture changes into the support posture with the axis L being parallel to the Y-axis direction perpendicular to the opposing direction X, the third flow channel <NUM>, the third opening <NUM>, and the inner wall surface <NUM> can be linearly aligned. In the case of the support posture, the second jig mounting portion <NUM> on the inner wall surface <NUM> is visible in the opposing direction X (the X-axis direction) from a location outside the valve body <NUM> through the third flow channel <NUM> and the switching flow channel <NUM>.

<FIG> illustrate the method for assembling the flow channel switching valve in <FIG>. Specifically, <FIG> is an exploded perspective view illustrating a state before the ball valve member <NUM>, the seat members <NUM>, and the sealing members <NUM> are inserted into the valve body <NUM>. <FIG> illustrates a state in which the ball valve member <NUM>, the seat members <NUM>, and the sealing members <NUM> are inserted in the valve body <NUM>, and the ball valve member <NUM> has the assembly posture with the axis L being parallel to the X-axis direction. <FIG> illustrates a state in which the ball valve member <NUM> is rotated from the assembly posture into the support posture with the axis L being parallel to the Y-axis direction in the valve chamber <NUM>. <FIG> illustrates a state in which the ball valve member <NUM> is rotated about the perpendicular axis K from the support posture with the axis L being parallel to the Y-axis direction into the support posture with the axis L being parallel to the Z-axis direction in the valve chamber <NUM>. <FIG> is an exploded perspective view illustrating a state before the driving section <NUM> is joined to the valve body <NUM>. In <FIG>, perspective views each containing a section are illustrated at (a), enlarged vertical cross-sectional views taken along line B-B in <FIG> are illustrated at (b), and enlarged cross-sectional views taken along line C-C in <FIG> are illustrated at (c).

As illustrated in <FIG>, the ball valve member <NUM> is first disposed such that the axis L is parallel to the X-axis direction, the second opening <NUM> faces upward, and the third opening <NUM> faces in the front direction. The ball valve member <NUM> is interposed between the seat members <NUM> in the X-axis direction (the opposing direction X). The sealing members <NUM> are fitted into the annular grooves 30a of the seat members <NUM>. As illustrated in <FIG>, the ball valve member <NUM>, the seat members <NUM>, and the sealing members <NUM> are inserted into the valve chamber <NUM> through the opening 110e of the valve body <NUM> with these being in contact with each other. At this time, the ball valve member <NUM> has the assembly posture with the axis L being parallel to the opposing direction X, and the sealing members <NUM> are in the restoration state in the valve chamber <NUM>. For this reason, the sealing members <NUM> do not elastically deform, the ball valve member <NUM>, the seat members <NUM>, and the sealing members <NUM> are smoothly installed in the valve chamber <NUM>. The opening 110e, the second opening <NUM>, and the inner wall surface <NUM> are linearly arranged in the Z-axis direction, and the first jig mounting portion <NUM> is visible in the Z-axis direction from a location outside the valve body <NUM> through the opening 110e and the switching flow channel <NUM>.

Subsequently, the hexagonal wrench, not illustrated, which serves as the rod-shaped jig, is inserted in the Z-axis direction into the second opening <NUM> through the opening 110e in a state illustrated in <FIG>, and the tip end portion thereof and the recessed portion 127a of the first jig mounting portion <NUM> are fit together. The ball valve member <NUM> is rotated in the direction (about the Z-axis direction) perpendicular to the axis L by rotating the hexagonal wrench in the counterclockwise direction illustrated by an arrow in <FIG>. As illustrated in <FIG>, the axis L of the ball valve member <NUM> is matched to the Y-axis direction, and the posture becomes the support posture. In this case, since the size W of the ball valve member <NUM> in the direction perpendicular to the direction of the axis L is larger than the size H thereof in the direction of the axis L (H < W), when the assembly posture of the ball valve member <NUM> changes into the support posture, the interval between the seat members <NUM> widens, and the state of the sealing members <NUM> changes from the restoration state into the compressed state. In the case of the support posture, the third flow channel <NUM>, the third opening <NUM>, and the inner wall surface <NUM> are linearly arranged in the X-axis direction, and the second jig mounting portion <NUM> is visible in the opposing direction X (the X-axis direction) from a location outside the valve body <NUM> through the third flow channel <NUM> and the switching flow channel <NUM>.

Subsequently, the hexagonal wrench, not illustrated, which serves as the rod-shaped jig, is inserted in the X-axis direction into the third opening <NUM> through the third flow channel <NUM> in a state illustrated in <FIG>, and the tip end portion thereof and the recessed portion 129a of the second jig mounting portion <NUM> are fit together. The ball valve member <NUM> is rotated about the perpendicular axis K parallel to the opposing direction X by rotating the hexagonal wrench in the counterclockwise direction illustrated by an arrow in <FIG>. As illustrated in <FIG>, the axis L is matched to the Z-axis direction, and the posture becomes the support posture. The seat members <NUM> support the ball valve member <NUM> that has the support posture such that the ball valve member <NUM> is rotatable about the axis L parallel to the Z-axis direction.

Subsequently, the prism portion <NUM> of the valve shaft <NUM> is inserted into the valve shaft insertion hole <NUM> of the ball valve member <NUM> that has the support posture and that is installed in the valve chamber <NUM>. The round columnar portion <NUM> of the valve shaft <NUM> is inserted into the bearing portion <NUM>, and the valve body <NUM> and the lower case <NUM> of the driving section case <NUM> are combined. The lower case <NUM> is exposed to ultrasonic, and the lower case <NUM> is welded to the valve body <NUM> by ultrasonic welding. The driving mechanism is incorporated with the lower case <NUM>, for example, by press-fitting the gear <NUM> to the round columnar portion <NUM> of the valve shaft <NUM> and is covered with the upper case <NUM>, the driving section <NUM> is assembled, and the flow channel switching valve <NUM> is completed.

The flow channel switching valve <NUM> according to the present embodiment exerts the same effects as those of the flow channel switching valve <NUM> according to the first embodiment described above.

In the embodiments described above, the seat members <NUM> and the sealing members <NUM> are separated components. However, the seat members <NUM> and the sealing members <NUM> may be integrated with each other. For example, the sealing members <NUM>, which are the O-rings, may be omitted, the seat members <NUM> may be composed of an elastic material and may be disposed as to be in direct contact with the valve body <NUM>. With this structure, portions of the seat members <NUM> in contact with the valve body <NUM> serve as the sealing members.

In the first embodiment described above, the diameters of the first opening <NUM>, the second opening <NUM>, and the third opening <NUM> of the ball valve member <NUM> are equal to each other but are not limited thereto. For example, the diameters of the first opening <NUM> and the third opening <NUM>, which are the two valve member openings opposite each other with the axis L interposed therebetween, may be smaller than the diameter of the second opening <NUM>, which is the other valve member opening. The diameter of the first opening <NUM> and the diameter of the third opening <NUM> may be equal to each other or may differ from each other. With this structure, the inner wall surface <NUM> of the ball valve member <NUM> on which the jig mounting portion <NUM> is disposed is opposite the second opening <NUM> and is visible from the outside through the second flow channel <NUM> and the second opening <NUM> that linearly extend with the ball valve member <NUM> installed in the valve chamber <NUM>. The diameter of the second flow channel <NUM> is larger than the diameter of the second opening <NUM>.

In this way, the rotational position of the ball valve member <NUM> can be checked and set by inserting a rod-shaped positioning jig that has the same diameter as that of the second opening <NUM> into the second flow channel <NUM> during the assembly of the flow channel switching valve <NUM>. That is, in the case where the rotational position of the ball valve member <NUM> is correct during the assembly, the second opening <NUM> of the ball valve member <NUM> faces the second flow channel <NUM>. For this reason, the positioning jig can be deeply inserted, and the positioning jig enables the ball valve member <NUM> to be secured at the correct rotational position. In the case where the rotational position of the ball valve member <NUM> is not correct during the assembly, the second opening <NUM> of the ball valve member <NUM> does not face the second flow channel <NUM>. For this reason, the positioning jig cannot be deeply inserted. In particular, in the case where the first opening <NUM> or the third opening <NUM> of the ball valve member <NUM> faces the second flow channel <NUM>, it is difficult to identify the second opening <NUM> even by looking into the second flow channel <NUM>. For this reason, inserting the positioning jig makes is possible to recognize that the rotational position of the ball valve member <NUM> is shifted, and the flow channel switching valve <NUM> can be more efficiently assembled. In the case where the ball valve member <NUM> includes two valve member openings (for example, only the first opening <NUM> and the second opening <NUM>), the same effects can be exerted in a manner in which the diameter of one of the valve member openings (the first opening <NUM>) is made smaller than the diameter of the other valve member opening (the second opening <NUM>). Also, a structure with different sizes of valve member openings can also be applied to a ball valve element with a recessed jig mounting portion provided on the outer surface.

The ball valve member <NUM> composed of synthetic resin is manufactured by injecting molten resin into a cavity C of a mold. <FIG> and <FIG> illustrate states during manufacture of the ball valve member <NUM>. <FIG> and <FIG> schematically illustrate states before and after mold pieces are inserted into the cavity of the mold that is used for manufacturing the ball valve member. In the figures, plan views are illustrated at (a), and front views are illustrated at (b).

During the manufacture of the ball valve member <NUM>, a second mold piece K2 that has the same diameter as the diameter of the second opening <NUM> and that has a cylindrical shape is inserted in a first direction (upward in the figures at (a), or the direction from the front to the rear at (b)) into the cavity C. A first mold piece K1 that has the same diameter as the diameter of the first opening <NUM> and that has a cylindrical shape is inserted in a second direction (the direction from the left to the right in the figures at (a) and (b)) perpendicular to the first direction into the cavity C, and a tip end surface K1a of the first mold piece K1 is brought into close contact with an outer circumferential surface K2a of the second mold piece K2. Similarly, a third mold piece K3 that has the same diameter as the diameter of the third opening <NUM> and that has a cylindrical shape is inserted in the direction opposite the second direction (the direction from the right to the left in the figures at (a) and (b)), and a tip end surface K3a of the third mold piece K3 is brought into close contact with the outer circumferential surface K2a of the second mold piece K2. The molten resin is injected into the cavity C.

The tip end surface K1a of the first mold piece K1 has a concave surface along the outer circumferential surface K2a of the second mold piece K2. For this reason, a part (designated by a reference sign E) of a circumferential edge portion of the tip end surface K1a is pointed. The diameter of the second opening <NUM> of the ball valve member <NUM> is equal to the diameter of the first opening <NUM>, and the diameter of the second mold piece K2 is equal to the diameter of the first mold piece K1. Consequently, the part E of the circumferential edge portion of the tip end surface K1a of the first mold piece K1 is very thin and is pointed. Accordingly, the rigidity of the part E of the first mold piece K1 decreases, and there is a possibility that the first mold piece K1 cannot be repeatedly used. The same is true for the third mold piece K3. The thicknesses of the parts E of the circumferential edge portions of the tip end surfaces K1a and K3a of the first mold piece K1 and the third mold piece K3 can be increased in a manner in which the diameter of the first opening <NUM> and the diameter of the third opening <NUM> are made smaller than the diameter of the second opening <NUM> as described above. For this reason, the rigidity of the parts E of the first mold piece K1 and the third mold piece K3 can be increased, and durability can be effectively improved. The same is true for the manufacture of the ball valve member that includes the two valve member openings.

Although embodiments of the present invention have been described above, the present invention is not limited by these embodiments.

<NUM> ··· flow channel switching valve, <NUM> ··· valve body, 10a ··· left side wall portion, 10b ··· front wall portion, 10c ··· right side wall portion, 10e ··· opening, <NUM> ··· first flow channel, <NUM> ··· second flow channel, <NUM> ··· third flow channel, 11a, 12a, 13a ··· opening, <NUM> ··· valve chamber, <NUM> ··· ball valve member, <NUM> ··· first opening, <NUM> ··· second opening, <NUM> ··· third opening, <NUM> ··· valve shaft insertion hole, <NUM> ··· switching flow channel, <NUM> ··· seat member, 30a ··· annular groove, <NUM> ··· sealing member, <NUM> ··· driving section, <NUM> ··· gear, <NUM> ··· driving section case, <NUM> ··· lower case, 43a ··· bottom wall, 43b ··· rib, <NUM> ··· upper case, <NUM> ··· bearing portion, <NUM> ··· valve shaft, <NUM> ··· round columnar portion, <NUM> ··· prism portion, <NUM> ··· stopper portion, <NUM> ··· O-ring, M ··· weld portion, C ··· cavity, K1 ··· first mold piece, K1a ··· tip end surface, K2 ··· second mold piece, K2a ··· outer circumferential surface, K3 ··· third mold piece, K3a ··· tip end surface, E ··· part of a circumferential edge portion of an tip end surface.

Claim 1:
A flow channel switching valve (<NUM>) comprising: a valve body (<NUM>) that has a valve chamber (<NUM>) and flow channels (<NUM>, <NUM>, <NUM>) in communication with the valve chamber (<NUM>); a valve member (<NUM>) that is installed in the valve chamber (<NUM>) and that has a switching flow channel (<NUM>) therein for switching between connections of the flow channels (<NUM>, <NUM>, <NUM>) depending on a rotational position of the valve member (<NUM>); a pair of seat members (<NUM>) that is installed in the valve chamber (<NUM>) in an interval, that interposes the valve member (<NUM>) therebetween, and that rotatably supports the valve member (<NUM>); a sealing member (<NUM>) that is disposed between each seat member (<NUM>) and the valve body (<NUM>); and a rotation driving section that causes the valve member (<NUM>) to rotate about a rotation axis,
wherein the valve body (<NUM>) is integrally provided with the flow channels (<NUM>, <NUM>, <NUM>),
wherein the valve body (<NUM>) has an opening that is in communication with the valve chamber (<NUM>) and that is used for inserting the valve member (<NUM>), the pair of seat members (<NUM>), and the sealing member (<NUM>) during assembly,
wherein a size of the valve member (<NUM>) in a direction of the rotation axis is smaller than a size thereof in a direction perpendicular to the rotation axis, and
wherein a first jig mounting portion (<NUM>) for rotating the valve member (<NUM>) in the perpendicular direction is disposed on an inner wall surface of the valve member (<NUM>) that is visible from a location outside the valve body (<NUM>) through the opening or the flow channels (<NUM>, <NUM>, <NUM>),
wherein the valve member (<NUM>) has three valve member openings (<NUM>, <NUM>, <NUM>) that face in the direction perpendicular to the rotation axis and that are connected to each other by using the switching flow channel (<NUM>),
wherein the three valve member openings (<NUM>, <NUM>, <NUM>) are arranged about the rotation axis in an interval of <NUM> degrees,
wherein diameters of two valve member openings (<NUM>, <NUM>) opposite each other with the rotation axis interposed therebetween among the three valve member openings are smaller than a diameter of the other valve member opening (<NUM>),
wherein the inner wall surface (<NUM>) of the valve member (<NUM>) on which the first jig mounting portion (<NUM>) is disposed is opposite the other valve member opening (<NUM>).