Patent Description:
An example of an existing flow channel switching valve is disclosed in Patent Literature <NUM>. The flow channel switching valve includes a valve body that has a valve chamber, a valve member that is disposed in the valve chamber, a valve shaft that is connected to the valve member, and a rotational driving section that includes, for example, a drive gear and a motor that rotationally drives the valve member via the valve shaft. Further prior art is described in Patent Literature <NUM> to <NUM>.

The valve member of the flow channel switching valve has a hexagonal vertical through hole. The valve shaft having a hexagonal cross-section is inserted into an upper portion of the vertical through hole. As a result, the valve member is connected to the valve shaft. Rotation of the valve shaft makes the valve member rotating. In addition, the valve member has a circular transverse hole that is selectively communicated with two outflow ports formed in the valve body.

However, in the valve member of the flow channel switching valve described above, since a corner portion of the hexagonal vertical through hole is disposed in a beam part between the vertical through hole and the transverse hole, the beam part has a thinner shape. Thus, in manufacturing the valve member by injection molding, resin flows may meet in the beam part. This may generate a weld line and decrease the rigidity of the beam part.

In view of this, it is an object of the present invention to provide a flow channel switching valve that can effectively suppress decreasing the rigidity of a beam part of a valve member.

To achieve the object described above, a flow channel switching valve of the present invention is defined in appended claim <NUM> and includes a valve body that has a valve chamber and flow channels in communication with the valve chamber, a valve member that is rotatably installed in the valve chamber and that switches between connections of the flow channels depending on a rotational position of the valve member, a valve shaft that is mounted in the valve member along a rotational axis of the valve member, and a driving section that rotates the valve member via the valve shaft. The valve member has a transverse hole in communication with a switching flow channel formed in the valve member, and a vertical hole in which the valve shaft is inserted. When viewed in the direction of the rotational axis, the vertical hole has an outward convex corner portion, and the corner portion is shifted from a beam part between the transverse hole and the vertical hole.

In the present invention, the vertical hole is in communication with the switching flow channel.

In the present invention, the vertical hole has a polygonal shape.

In the present invention, when viewed in the direction of the rotational axis, the transverse hole is formed such that a center line of the transverse hole is perpendicular to a side portion of the polygonal shape.

In the present invention, the vertical hole preferably has a polygonal shape with corner portions in multiples of three or four.

In the present invention, the vertical hole preferably has a quadrangular shape.

In the present invention, the vertical hole preferably has a triangular shape.

In the present invention, the valve member is resin-molded in a spherical shape and has a gate mark only on an outer surface of a wall portion that faces the vertical hole.

According to the present invention, the valve member in which the valve shaft is mounted has the transverse hole in communication with the switching flow channel formed in the valve member, and the vertical hole in which the valve shaft is inserted. When viewed in the direction of the rotational axis of the valve member, the vertical hole has the outward convex corner portion, and the corner portion is shifted from the beam part between the transverse hole and the vertical hole. In this way, it is possible to avoid the beam part of the valve member having a thinner shape and effectively suppress decreasing the rigidity of the beam part of the valve member. Due to the vertical hole in which the valve shaft is inserted has a polygonal shape such as a triangular shape, a quadrangular shape, a hexagonal shape, or an octagonal shape, the valve member has a relatively simple structure and can be easily manufactured.

A flow channel switching valve according to an embodiment of the present invention will now be described with reference to <FIG>.

<FIG> is a perspective view containing a cross-section of the flow channel switching valve according to the embodiment of the present invention. <FIG> is a cross-sectional view taken along line A-A in <FIG>. <FIG> is a perspective view of a ball valve member and a valve shaft of the flow channel switching valve in <FIG>. <FIG> is a plan view of the ball valve member that the flow channel switching valve according to the present embodiment includes. <FIG> are plan views illustrating modifications of the ball valve member. 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 figures, an X-axis direction represents a left-and-right direction, a Y-axis direction represents a front-and-rear direction (a front-back 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. A direction along a rotational axis of the valve member (a direction of a rotational axis) represents a vertical direction, and a direction perpendicular to the rotational axis represents a transverse direction.

As illustrated in <FIG> and <FIG>, a flow channel switching valve <NUM> according to the present embodiment includes a valve body <NUM>, a ball valve member <NUM>, seat members <NUM>, sealing members <NUM>, a driving section <NUM>, and a valve shaft <NUM>. The flow channel switching valve <NUM> further includes a potentiometer shaft <NUM> corresponding to a rotational angle output shaft, a potentiometer base <NUM> corresponding to a base body, and a potentiometer <NUM> corresponding to a rotational angle detection portion.

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 formed on a left side wall portion 10a of the valve body <NUM>. A second flow channel <NUM> that is linear is formed on a front wall portion 10b of the valve body <NUM>. A third flow channel <NUM> that is plane-symmetrical with the first flow channel <NUM> and that has a substantially L-shape is formed on a right side wall portion 10c of the valve body <NUM>. An opening 11a of the first flow channel <NUM>, an opening 12a of the second flow channel <NUM>, and an opening 13a of the third flow channel <NUM> are directed in the same direction (the front 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 formed in the valve body <NUM>. Two flow channels or four or more flow channels in communication with the valve chamber <NUM> may be formed.

The ball valve member <NUM> is composed of a 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> described later and is installed in the valve chamber <NUM>. The ball valve member <NUM> has a first opening <NUM> that is a transverse hole opened toward the left-hand direction, a second opening <NUM> that is a transverse hole opened toward the front direction, and a third opening <NUM> that is a transverse hole opened toward the right-hand direction when the ball valve member <NUM> is located at a rotational position illustrated in <FIG>. A switching flow channel <NUM> is formed in the ball valve member <NUM>. The switching flow channel <NUM> 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. In other words, the first opening <NUM>, the second opening <NUM>, and the third opening <NUM> are connected to the switching flow channel <NUM>. For example, the ball valve member <NUM> may have only the first opening <NUM> and the second opening <NUM>. The ball valve member <NUM> may have the switching flow channel <NUM> that has a substantially L-shape in a plan view and that connects the first opening <NUM> and the second opening <NUM> to each other when the ball valve member <NUM> is located at the rotational position illustrated in <FIG>. In the present embodiment, the ball valve member <NUM> is used as the valve member, but a non claimed columnar valve member may be used.

The switching flow channel <NUM> switches between the connections among the first flow channel <NUM>, the second flow channel <NUM>, and the third flow channel <NUM> 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> is formed in an upper portion of the ball valve member <NUM>. A valve shaft insertion hole <NUM> is a vertical hole in which the valve shaft <NUM> described later is inserted. The valve shaft insertion hole <NUM> is in communication with the switching flow channel <NUM>. The valve shaft insertion hole <NUM> is inserted the valve shaft <NUM> therein. The valve shaft insertion hole <NUM> is formed such that rotation of the valve shaft <NUM> makes the ball valve <NUM> rotating about an axis L corresponding to a rotational axis. Specifically, the valve shaft insertion hole <NUM> has the same shape as a cross-sectional shape (a transverse cross-sectional shape) in the direction perpendicular to the axial direction of the prism portion <NUM> of the valve shaft <NUM>. In the present embodiment, when viewed in the direction along the axis L (the direction of the rotational axis), the valve shaft insertion hole <NUM> has a square shape as illustrated in <FIG>.

The valve shaft insertion hole <NUM> has a square shape and has four outward convex corner portions 24a. Each of the four corner portions 24a is shifted from a beam part 26a between the first opening <NUM> and the valve shaft insertion hole <NUM>, a beam part 26b between the second opening <NUM> and the valve shaft insertion hole <NUM>, and a beam part 26c between the third opening <NUM> and the valve shaft insertion hole <NUM>. In other words, each of the four corner portions 24a of the valve shaft insertion hole <NUM> is disposed facing a peripheral wall part 27a between the first opening <NUM> and the second opening <NUM>, a peripheral wall part 27b between the second opening <NUM> and the third opening <NUM>, or a peripheral wall part 27c between the third opening <NUM> and the first opening <NUM>. The valve shaft insertion hole <NUM> faces a bottom wall part <NUM> corresponding to a lower wall part of the ball valve member <NUM>, in the direction along the axis L.

<FIG> illustrate the modifications that can be employed in place of the valve shaft insertion hole <NUM>. <FIG> (not forming part of the claimed invention) illustrates a valve shaft insertion hole 24A formed by curving each side of a square shape inward. <FIG> (not forming part of the claimed invention) illustrates a valve shaft insertion hole 24B having a cross shape. <FIG> illustrates a valve shaft insertion hole 24C having an octagonal shape. In the valve shaft insertion holes 24A, 24B, and 24C, each of the corner portions 24a is also shifted from the beam parts 26a, 26b, and 26c as the valve shaft insertion hole <NUM> in the present embodiment. That is, each of the corner portions 24a is disposed facing the peripheral wall parts 27a, 27b, or 27c.

In addition, <FIG> illustrate ball valve members 20D and 20E that have the first opening <NUM> and the second opening <NUM>. The first opening <NUM> and the second opening <NUM> are two transverse holes and are formed about the axis L. <FIG> illustrates the modification with a valve shaft insertion hole 24D having a triangular shape. <FIG> illustrates the modification with a valve shaft insertion hole 24E having a hexagonal shape. In the valve shaft insertion holes 24D and 24E, each of the corner portions 24a is also shifted from the beam parts 26a and 26b as the valve shaft insertion hole <NUM> in the present embodiment. That is, each of the corner portions 24a is disposed facing the peripheral wall parts 27a or 27b. In the structure employing the ball valve members 20D and 20E, each of the flow channels of the valve body <NUM> is disposed to correspond to the first opening <NUM> and the second opening <NUM> illustrated in <FIG>. The dashed lines in <FIG> and <FIG> show the cross-sectional shapes of the flow channels including the transverse holes in each of the valve members.

In any of ball valve members illustrated in <FIG>, each of the corner portions 24a of the valve shaft insertion hole is also shifted from the beam parts 26a, 26b, and 26c between the transverse holes and the vertical hole (the valve shaft insertion hole). That is, each of the corner portions 24a is disposed facing the peripheral wall parts 27a, 27b, or 27c. In the ball valve member having the valve shaft insertion hole with a polygonal shape such as a triangular shape, a quadrangular shape, a hexagonal shape, or an octagonal shape, when viewed in the direction along the axis L (the direction of the rotational axis), a center line (an axis) of the transverse hole is perpendicular to a side portion of the polygonal shape in the valve shaft insertion hole. In the present embodiment, when viewed in the direction along the axis L, each of the center lines of the first opening <NUM>, the second opening <NUM>, and the third opening <NUM> is perpendicular to the side portion of the quadrangular shape in the valve shaft insertion hole <NUM>. The first opening <NUM>, the second opening <NUM>, and the third opening <NUM> are the transverse holes.

The seat members <NUM> are composed of, for example, synthetic resin such as polytetrafluoroethylene (PTFE) and have an annular shape. 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> that the ball valve member <NUM> is disposed therebetween rotatably support the ball valve member <NUM> in the valve chamber <NUM>.

The sealing members <NUM> are, for example, O-rings composed of an elastic material such as a rubber material, one of which is disposed between one of the seat members <NUM> and the left side wall portion 10a of the valve body <NUM> in a compressed state, and the other of which is disposed between the other seat member <NUM> and the right side wall portion 10c of the valve body <NUM> 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>. The flow channel switching valve may have a structure omitting the sealing members <NUM> and employing seat members <NUM> that are composed of an elastic material such as a rubber material and that have the function of the sealing members instead.

The driving section <NUM> includes a driving mechanism, a lower case <NUM>, and an upper case that is not illustrated. The driving mechanism includes a combination of a motor, not illustrated, and a speed reducer that includes a gear <NUM>. The lower case <NUM> is composed of resin and in which the driving mechanism is installed. The upper case is mounted on the lower case <NUM> by a screw fastening structure, a snap-fit structure, or other mounting structure. The driving section <NUM> rotates the ball valve member <NUM> about the axis L via the valve shaft <NUM> described later.

The lower case <NUM> includes a cylindrical bearing portion <NUM> that is integrated with the center of a bottom wall 43a. The valve shaft <NUM> is disposed in the bearing portion <NUM>, and the bearing portion <NUM> rotatably supports the valve shaft <NUM>. An inner peripheral wall portion 43b has a substantially square tube shape and is formed at the bottom wall 43a of the lower case <NUM>. The inner peripheral wall portion 43b is combined with an upper end portion of the valve body <NUM> and is joined to each other (by ultrasonic welding in the present embodiment). The lower case <NUM> and the valve body <NUM> may be assembled to each other, for example, in a screw fastening structure.

The valve shaft <NUM> is composed of synthetic resin, has a columnar shape that linearly extends overall, and includes a round columnar portion <NUM> and a prism portion <NUM>. The prism portion <NUM> is coaxially connected to the lower end of the round columnar portion <NUM>. The valve shaft <NUM> extends along the axis L.

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

In addition, a groove is formed on the lower end portion of the round columnar portion <NUM> over the entire circumference. The groove is disposed at a position above the stopper portion <NUM>. An O-ring <NUM> is composed of, for example, a rubber material and has an annular shape. The O-ring <NUM> is fitted in the groove. The round columnar portion <NUM> is disposed 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 its outside.

The gear <NUM> that the driving mechanism of the driving section <NUM> includes is mounted on an upper end portion of the round columnar portion <NUM> by press-fitting. A planar surface 51a that inhibits the press-fitted gear <NUM> from slipping is disposed on the upper end portion of the round columnar portion <NUM>. The gear <NUM> may be mounted on the valve shaft <NUM> by a method other than press-fitting.

The prism portion <NUM> has a columnar shape of which the transverse cross-sectional shape is a square shape. The prism portion <NUM> is inserted in the valve shaft insertion hole <NUM> of the ball valve member <NUM> and is consequently mounted in the ball valve member <NUM> along the axis L. As a result, the axis L of the ball valve member <NUM> serves as the rotational axis of the valve shaft <NUM>. Rotation of the gear <NUM> makes the valve shaft <NUM> rotating about the axis L. The valve shaft insertion hole <NUM> has the same square shape as the transverse cross-sectional shape of the prism portion <NUM>. For this reason, the valve shaft insertion hole <NUM> and the prism portion <NUM> fit together, and rotation of the valve shaft <NUM> makes the ball valve member <NUM> rotating about the axis L. The outer diameter of the prism portion <NUM> is smaller than the outer diameter of the stopper portion <NUM>.

A mounting hole <NUM> that has a substantially round columnar shape along the axis L is formed at the center of an end surface 51b of the round columnar portion <NUM> that faces upward. A potentiometer shaft <NUM> described later is press-fitted in the mounting hole <NUM>.

The potentiometer shaft <NUM> is composed of, for example, metal such as stainless steel or brass, or synthetic resin such as polyphenylene sulfide (PPS). The potentiometer shaft <NUM> is formed separately from the valve shaft <NUM>. The potentiometer shaft <NUM> is press-fitted in the mounting hole <NUM> of the valve shaft <NUM> and is coaxially secured to and mounted in the valve shaft <NUM>. The potentiometer shaft <NUM> has a fitting shaft portion <NUM> with D-shape in its upper end. The fitting shaft portion <NUM> is fitted a rotor <NUM> of the potentiometer <NUM> described later.

The potentiometer base <NUM> is composed of synthetic resin and includes a base main body portion <NUM> and a meter mounting portion <NUM>, integrally formed with each other. The base main body portion <NUM> has a substantially flat plate shape and is secured to a boss (not illustrated) that protrudes upward from the bottom wall 43a of the lower case <NUM> by using screws <NUM>. The meter mounting portion <NUM> has a substantially disk shape and the potentiometer <NUM> described later is mounted in the center of the meter mounting portion <NUM>.

The potentiometer <NUM> is a rotational angle sensor for detecting a rotational angle. The potentiometer <NUM> includes the rotor <NUM> that has a disk shape and a meter main body portion <NUM> corresponding to a signal output portion that rotatably supports the rotor <NUM> and that outputs a signal (voltage) depending on the rotational angle of the rotor <NUM>. A fitting hole that has a D-shape in a plan view is formed at the center of the rotor <NUM>. The fitting shaft portion <NUM> of the potentiometer shaft <NUM> extends through the fitting hole and is fitted in the fitting hole. Rotation of the fitting shaft portion <NUM> makes the rotor <NUM> rotating. Consequently, the potentiometer <NUM> detects the rotational angle of the potentiometer shaft <NUM> (that is, the valve shaft <NUM> and the ball valve member <NUM>) about the axis L.

In the flow channel switching valve <NUM>, the 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 about the axis L. Rotation of the valve shaft <NUM> makes the ball valve member <NUM> rotating about the axis L and locating at each rotational position. This achieves connections of the flow channels depending on the rotational position of the ball valve member <NUM>. The potentiometer shaft <NUM> is rotated about the axis L together with the valve shaft <NUM>, and the potentiometer <NUM> outputs the signal depending on the rotational angle of the potentiometer shaft <NUM>. The rotational position of the ball valve member <NUM> can be monitored based on the signal that is outputted from the potentiometer <NUM>.

In the flow channel switching valve <NUM> according to the present embodiment described above, the ball valve member <NUM> in which the valve shaft <NUM> is mounted has the first opening <NUM>, the second opening <NUM>, the third opening <NUM>, and the valve shaft insertion hole <NUM>. The first opening <NUM>, the second opening <NUM>, and the third opening <NUM> are the transverse holes in communication with the switching flow channel <NUM> formed in the ball valve member <NUM>. The valve shaft insertion hole <NUM> is the vertical hole in which the valve shaft <NUM> is inserted. The valve shaft insertion hole <NUM> has the outward convex corner portions 24a, and the corner portions 24a are shifted from the beam part 26a between the first opening <NUM> and the valve shaft insertion hole <NUM>, the beam part 26b between the second opening <NUM> and the valve shaft insertion hole <NUM>, and the beam part 26c between the third opening <NUM> and the valve shaft insertion hole <NUM>. In this way, it is possible to avoid the beam parts 26a, 26b, and 26c of the valve member <NUM> having a thinner shape and effectively suppress decreasing the rigidity of the beam parts 26a, 26b, and 26c of the valve member <NUM>. Due to the valve shaft insertion hole <NUM> has a quadrangular shape, the valve member <NUM> has a relatively simple structure and can be easily manufactured.

The ball valve member <NUM> is molded by injecting molten resin into a cavity of a mold (that is, resin molding). In the mold, a gate (a resin inlet) for injecting resin into the cavity is formed at a point corresponding to the outer surface of the bottom wall part <NUM> facing the valve shaft insertion hole <NUM> that is a vertical hole. In particular, the gate is preferably formed at or near the area where the axis line L passes through on the outer surface of the bottom wall part <NUM>. As a result, an unevenness (a gate mark), which is a trace of the gate, is formed only on the outer surface of the bottom wall part <NUM>. It is possible to avoid gate mark formation on the beam parts 26a, 26b, and 26c and peripheral wall parts 27a, 27b, and 27c on the outer surface of the ball valve member <NUM>, which are in contact with the seat members <NUM>. This prevents the gate mark from coming into contact with the seat members <NUM>, thereby improving sealing performance and allowing the ball valve member <NUM> to slide smoothly.

The embodiment of the present invention is described above. However, the embodiment is one example, and the present invention is not limited to the embodiment. An embodiment obtained by appropriately adding, removing, or modifying components according to the embodiment described above by a person skilled in the art, and an embodiment obtained by appropriately combining features of the embodiment are included in the scope of the present invention without departing from the scope of the present invention as defined by the appended claims.

Claim 1:
A flow channel switching valve comprising:
a valve body (<NUM>) that has a valve chamber (<NUM>) and flow channels in communication with the valve chamber;
a valve member (<NUM>) that is rotatably installed in the valve chamber (<NUM>) and that switches between connections of the flow channels depending on a rotational position of the valve member;
a valve shaft (<NUM>) that is mounted in the valve member (<NUM>) along a rotational axis of the valve member; and
a driving section that rotates the valve member via the valve shaft,
wherein the valve member (<NUM>) has two or three transverse holes (<NUM>, <NUM>, <NUM>) in communication with a switching flow channel formed in the valve member, and a vertical hole (<NUM>) in which the valve shaft (<NUM>) is inserted. transverse holes (<NUM>, <NUM>, <NUM>) and peripheral wall parts in between the wherein the vertical hole (<NUM>) has a polygonal shape,
wherein when viewed in the direction of the rotational axis, the vertical hole (<NUM>) has multiple outward convex corner portions, and each corner portion is disposed facing a peripheral wall part,
wherein the vertical hole (<NUM>)
is in communication with the switching flow channel,
wherein when viewed in the direction of the rotational axis, each transverse hole (<NUM>, <NUM>, <NUM>) is formed
such that a center line of the transverse hole (<NUM>, <NUM>, <NUM>) is perpendicular to a side portion of the (<NUM>, <NUM>, <NUM>) polygonal shape corresponding to a beam part between the transverse hole and the vertical hole next to the transverse hole, and
wherein the valve member is resin-molded in a spherical shape characterised in that the valve member (<NUM>) has a gate mark only on an outer surface of a wall portion that faces the vertical hole.