Patent Description:
Generally, heat-pump type air conditioning systems include a flow path switching valve such as a four-way switching valve and a flow path switching valve in addition to a compressor, an outdoor heat exchanger, an indoor heat exchanger, and an expansion valve, etc. For example, a flow path switching valve is applied in the heat-pump type air conditioning system indicated in <FIG> and <FIG>.

As illustrated in <FIG> and <FIG>, a heat-pump type air conditioning system <NUM> performs the switching of operation modes (cooling operation and heating operation) at a flow path switching valve <NUM>. Basically, the heat-pump type air conditioning system <NUM> includes a compressor <NUM>, an outdoor heat exchanger <NUM>, an indoor heat exchanger <NUM>, a cooler expansion valve <NUM>, and a heater expansion valve <NUM>, and the flow path switching valve <NUM> that is the flow path switching valve is arranged between them. The flow path switching valve <NUM> is a valve having six ports pA, pB, pC, pD, pE, and pF. Each of said components is connected a flow path formed, for example, by conduits (pipings).

As illustrated in <FIG>, in the heat-pump type air conditioning system <NUM>, when a cooling operation mode is selected, refrigerants with high temperature and high pressure are discharged from the compressor <NUM> and are directed to the outdoor heat exchanger <NUM> via ports pA and pB of the flow path switching valve <NUM>. In the outdoor heat exchanger <NUM>, heat of the refrigerants directed to the outdoor heat exchanger <NUM> is exchanged with outdoor air, and the refrigerants are condensed and become gas-liquid two-phase refrigerants with high pressure or liquid refrigerants, and are directed to the cooler expansion valve <NUM>.

The refrigerants with high pressure are depressurized by the cooler expansion valve <NUM>, and the depressurized refrigerants are introduced into the indoor heat exchanger <NUM> via the ports pE and pF of the flow path switching valve <NUM>. Heat of the refrigerants introduced into the indoor heat exchanger <NUM> is exchanged (cooled) with outdoor air, and the refrigerants are evaporated and become the refrigerant with low temperature and low pressure and are returned to the suction-side of the compressor <NUM> via the ports pC and pD of the flow path switching valve <NUM>.

On the other hand, as illustrated in <FIG>, in the heat-pump type air conditioning system <NUM>, when a heating operation mode is selected, the refrigerants with high temperature and high pressure are discharged from the compressor <NUM> and are directed to the indoor heat exchanger <NUM> via ports pA and pF of the flow path switching valve <NUM>. In the indoor heat exchanger <NUM>, heat of the refrigerants directed is exchanged with outdoor air, and the refrigerants are condensed (heated) and become gas-liquid two-phase refrigerants with high pressure or liquid refrigerants, and are directed to the heater expansion valve <NUM>.

The refrigerants with high pressure are depressurized by the heater expansion valve <NUM>, and the depressurized refrigerants are introduced into the outdoor heat exchanger <NUM> via the ports pC and pB of the flow path switching valve <NUM>. Heat of the refrigerants introduced into the outdoor heat exchanger <NUM> is exchanged with outdoor air, and the refrigerants are evaporated and become the refrigerant with low temperature and low pressure and are returned from the outdoor heat exchanger <NUM> to the suction-side of the compressor <NUM> via the ports pE and pD of the flow path switching valve <NUM>.

Slide-type flow path switching valves are known as the flow path switching valves incorporated in the aforementioned heat-pump type air conditioning systems (for example, Patent Document <NUM>). In the slide-type flow path switching valve described in Patent Document <NUM>, a main valve body slides and moves to switch flow paths. In addition, the main valve body of the slide-type flow path switching valve may be two slide valve bodies, for example, a high-pressure side slide valve body and a low-pressure side slide valve body combined together (Patent Document <NUM>).

<CIT>
describes a flow path change-over valve comprising a main valve housing, a valve seat surface, three ports opened on a valve seat surface, and a rotation valve core arranged on the valve seat surface. A low-pressure-side U-shaped turning communication path is formed in the rotation valve core to selectively communicate the ports, the valve seat surface is regarded as the lower side, the rotation valve core is formed by segmentation of a low-pressure path dividing part and a matrix portion, the low-pressure path dividing part forms the lower side or inner circumferential side portion of the low-pressure-side U-shaped turning communication path through division, the matrix portion forms the upper side or outer circumferential side portion of the low-pressure-side U-shaped turning communication path through division, the shape of a cross section of the low-pressure-side U-shaped turning communication path is set as a circular shape or an oval shape similar to the circular shape, and the cross section is set to be equivalent all over the total length from one end to the other end. <CIT> describes a six-way switching valve, wherein in each flow passage switching valve, a poppet type main valve elements are moved in synchronization with each other in main valve chambers defined by cylindrical main valve housing; thus, communication between ports can be switched. <CIT> describes a six-way directional valve, an outdoor unit having the same and an air conditioner are provided. The six-way directional valve includes: a valve body, defining a valve cavity therein, the valve cavity having a first side wall and a second side wall disposed oppositely to each other, the valve body being provided with a first connecting pipe to a sixth connecting pipe; a valve spool, movably disposed in the valve cavity, a first chamber being defined between the valve spool and the first side wall, a second chamber being defined between the valve spool and the second side wall, and a third chamber being defined between the valve spool, the first side wall and the second side wall; and a pilot valve assembly.

Document <CIT> is considered to be the closest prior art and discloses a flow path switching valve according to the preamble of claim <NUM>.

In recent year, concerns for energy saving have grown, and it is demanded to prevent initial leakage and leakage by durability deterioration (valve leakage) in flow path switching valves for switching flow paths, such as six-way switching valves, to further improve efficiency of the heat-pump type air conditioning systems. For example, in the slide-type flow path switching valve having a high-pressure side slide valve body and a low-pressure side slide valve body, high pressure is applied to the high-pressure side slide valve body. Accordingly, a sealing surface of the high-pressure side slide valve body easily deforms, and there is a concern that valve leakage occurs. Therefore, conventionally, development of flow path switching valve to prevent valve leakage have been urgent.

The present invention provides a flow path switching valve according to claim <NUM> and is suggested to solve the aforementioned problems, and objective thereof is to provide a flow path switching valve that can suppress deformation of the sealing surface and prevent valve leakage by improving rigidity of the high-pressure side slide valve body, and that contributes to improvement of efficiency of the heat-pump type air conditioning system.

To achieve the above objective, a flow path switching valve according to claim <NUM> is provided.

According to the present invention, a flow path switching valve that can suppress deformation of the sealing surface and prevent valve leakage by improving rigidity of the high-pressure side slide valve body, and that contributes to improvement of efficiency of the heat-pump type air conditioning system can be obtained.

In below, designs are described with the reference to figures. <FIG> and <FIG>, not representing the present invention, are vertical cross-sectional diagrams illustrating a flow path switching valve in a first design in which <FIG> illustrates a diagram during a cooling operation and <FIG> illustrates a diagram during a heating operation.

In the present specification, descriptions representing positions and directions such as above, below, right, left, front, and back, are presented according to the figures for convenience to avoid the descriptions to become complicated, and they do not necessarily indicate actual positions and directions when incorporated in a heat-pump type air conditioning system, etc. Furthermore, in figures, gaps formed between components or distances between components may be provided smaller or larger relative to dimensions of each component to facilitate understandings of the invention and to facilitate drawings of the figures.

A flow path switching valve <NUM> according to a first embodiment is, for example, a slide-type flow path switching valve <NUM> used in a heat-pump type air conditioning system <NUM> illustrated in <FIG> and <FIG>.

As illustrated in <FIG> and <FIG>, not representing the present invention, basically, the flow path switching valve <NUM> according to the first embodiment includes a cylindrical flow path valve main body <NUM> and a single electromagnetic four-way pilot valve as a pilot valve. Note that the flow path switching valve <NUM> of the first embodiment is a six-way switching valve including six ports, and each of the six ports corresponds with ports pA to pF of the flow path switching valve <NUM> and is labeled by the same signs.

The flow path valve main body <NUM> has a main valve housing <NUM> made of metal such as brass or stainless steel, etc. A first operation chamber <NUM>, a first piston <NUM>, a main valve chamber <NUM>, a second piston <NUM>, and a second operation chamber <NUM> are arranged in the main valve housing <NUM> from one end (upper stream end) in this order. Spring-loaded packings are attached to the first piston <NUM> and the second piston <NUM>, and an outer circumference of the spring-loaded packing is pressure-welded on an inner circumferential surface of the main valve housing <NUM> to airtightly divide the main valve housing <NUM>.

The main valve housing <NUM> has a body 11c with large diameter. An upper connection lid 11d with thick disc-shape is airtightly attached to an upper opening of the body 11c. A center hole is provided to the upper connection lid 11d. A first piston portion 11a formed of a pipe member with short diameter is airtightly adhered to the center hole of the upper connection lid 11d by brazing or welding, etc. (by brazing in the following embodiment). The first piston <NUM> is arranged to the first piston portion 11a.

A lower connection lid 11e with thick disc-shape is airtightly attached a lower opening of the body 11c. A center hole is also provided to the lower connection lid 11e. A second piston portion 11b formed of a pipe member with short diameter is airtightly adhered to the center hole of the lower connection lid 11e by brazing. The second piston <NUM> is arranged to the second piston portion 11b.

An upper end lid member 11A with thin disc-shape is airtightly adhered to an upper end of the first piston portion 11a of the main valve housing <NUM> by brazing, etc. The upper end lid member 11A defines the first operation chamber <NUM> in which volume thereof is variable. A lower end lid member 11B with thin disc-shape is airtightly adhered to a lower end of the second piston portion 11b of the main valve housing <NUM> by brazing, etc..

The lower end lid member 11B defines the second operation chamber <NUM> in which volume thereof is variable. A port p11 and a port p12 are attached to a center of the upper end lid member 11A and a center of the lower end lid member 11B, respectively. The ports p11 and p12 are ports for introducing and discharging liquid with high pressure to the first operation chamber <NUM> and the second operation chamber <NUM>.

A main valve chamber <NUM> of the main valve housing <NUM> is a space provided inside the main valve housing <NUM>. Total of six ports are provided to the main valve chamber <NUM>. For example, a first main valve seat <NUM> made of metal is airtightly adhered to an inner circumference of the main valve housing <NUM> at left center of the main valve chamber <NUM> by brazing, etc..

A surface (right surface) of the first main valve seat <NUM> is a flat valve seating surface. Three ports formed of pipe joints extending leftward are opened and aligned vertically (that is, aligned in the axial direction O) at substantially even intervals on the valve seating surface of the first main valve seat <NUM>. The three ports are a port pB, a port pA and a port pF from the upper end-side.

Furthermore, for example, a second main valve seat <NUM> made of metal is airtightly adhered to the inner circumference of the main valve housing <NUM> at right center of the main valve chamber <NUM> (a position facing the first main valve seat <NUM>, that is, a position opposite the first main valve seat <NUM> across an axis O) by brazing, etc. A surface (left surface) of the second main valve seat <NUM> is a flat valve seating surface. Three ports formed of pipe joints extending rightward are opened and aligned vertically (that is, aligned in the axial direction O) at substantially even intervals on the valve seating surface of the second main valve seat <NUM>. The three ports are a port pC, a port pD and a port pE from the upper end-side.

The port pB, port pA, and port pF provided to the first main valve seat <NUM>, and the ports pC, port pD, and port pE provided to the second main valve seat <NUM> are arranged at positions facing each other (opposite positions across the axis O). In the present examples, ports pA to pF provided to the first main valve seat <NUM> and the second main valve seat <NUM> have substantially same diameters.

A slide-type main valve body <NUM> is arranged movably in the axial direction O (vertical direction) in the body 11c of the main valve housing <NUM>. The main valve body <NUM> is a rectangular valve body having an annular sealing surface in race-track shape. Both side surfaces (left surface and right surface) of the main valve body <NUM> are freely slidably in contact with the valve seating surfaces of the first main valve seat <NUM> and the second main valve seat <NUM>, respectively. In the present examples, dimensions of the main valve body <NUM> in the right-left direction and the front-back direction are set to be equivalent to or slightly larger than outer diameters of the first piston portion 11a and the second piston portion 11b of the main valve housing <NUM>.

The main valve body <NUM> is formed of, for example, synthetic resins, and is formed by two components of a high-pressure side slide valve body 15A at the first main valve body <NUM>-side (left side) and a low-pressure side slide valve body 15B at the second main valve body <NUM>-side (right side).

The high-pressure side slide valve body 15A is a tubular member which does not have a ceiling on the right side (second main valve seat <NUM>-side). The high-pressure side slide valve body 15A is arranged to surround an end(a tip portion at the first main valve seat <NUM>-side) on the left side of the low-pressure side slide valve body 15B from the outer side. An inner brim 15a protrudes toward the inside from the left-surface side of the high-pressure side slide valve body 15A (the side opposite to the low-pressure side slide valve body 15B-side). An opening in a size that can selectively communicate two adjacent ports (pB and pA, or pA and pF) among three ports opened on the valve seating surface of the first main valve seat <NUM> is defined in the inner brim 15a. A left end surface (an end surface at the first main valve seat <NUM>-side) of the inner brim 15a is the annular sealing surface which is freely slidably in contact with the valve seating surface of the first main valve seat <NUM>.

As illustrated in <FIG>, not representing the present invention, a bridge <NUM>, which connects inner circumferential surfaces of the high-pressure side slide valve body 15A facing each other in a direction orthogonal to the axis O of the main valve chamber <NUM>, is provided on the inner circumferential surfaces. The bridge <NUM> is formed integrally with the high-pressure side slide valve body 15A. The bridge <NUM> extends in a direction orthogonal to the axial direction of the main valve chamber <NUM> and is a direction parallel with the seating surface of the first main valve seat <NUM>, and connects the inner circumferential surfaces of the high-pressure side slide valve body 15A facing each other. <FIG> is a main-section-enlarged horizontal cross-sectional diagram along A-A line in <FIG>.

In the high-pressure side slide valve body 15A, an end at the low-pressure side slide valve body 15B-side is a tip portion, and an end opposite to the tip portion (first main valve seat <NUM>-side) is a base portion. As illustrated in <FIG> and <FIG>, two openings which are respectively communicated with adjacent two ports are provided in the base portion of the high-pressure side slide valve body 15A, and the bridge <NUM> is formed of an end surface sandwiched by circular arcs of two openings. That is, the bridge <NUM> provided in the base portion of the high-pressure side slide valve body 15A. Note that, in the present example, although the openings formed in the base portion of the high-pressure side slide valve body 15A have the same shape as the ports to which the openings are communicated, the shapes of the openings may be different from the shape of the ports as long as required flow amount is ensured.

The convex portion 15b protruding toward the high-pressure side slide valve body 15A-side is provided in the low-pressure side slide valve body 15B. The convex portion 15b has an outer diameter substantially equal to or slightly smaller than an inner diameter of the high-pressure side slide valve body 15A and is formed integrally with the low-pressure side slide valve body 15B. A high-pressure side U-turn path 16A is defined in a space surrounded by an inner circumferential surface of the high-pressure side slide valve body 15A, and the convex portion 15b. The high-pressure side U-turn path 16A may selectively communicate two adjacent ports (pB and pA, or pA and pF) among three ports opened on the valve seating surface of the first main valve seat <NUM>. Fluids with relatively high pressure may be introduced in the high-pressure side U-turn path 16A.

Meanwhile, a low-pressure side U-turn path 16B is defined at the right surface side (side opposite to the high-pressure side slide valve body 15A) of the low-pressure side slide valve body 15B. The low-pressure side U-turn path 16B is formed of a bowl-shaped concavity that can selectively communicate two adjacent ports (pC and pD, or pD and pE) among three ports opened on the valve seating surface of the second main valve seat <NUM>. Fluids with relatively low pressure may be introduced in the low-pressure side U-turn path 16B.

In the present embodiment, by moving the main valve body <NUM> inside the main valve chamber <NUM>, two ports among three ports are selectively communicated via the high-pressure side U-turn path 16A. At the same time, two ports among another three ports are selectively communicated via the low-pressure side U-turn path 16B, and the other one port among three ports and the other one port among another three ports may be selectively communicated via the main valve housing <NUM>.

The high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B are slightly freely movable relative to each other in the right-left direction and are freely movable integrally in the vertical direction. Here, the right-left direction is a direction which is orthogonal to the axis O and in which the ports pB, pA, and pF provided in the first main valve seat <NUM>, and the ports pC, pD, and pE provided in the second main valve seat <NUM> face each other. In addition, the vertical direction is the axial direction O.

In the illustrated example, an O-ring <NUM> that is an annular sealing member is interposed between a step (inner circumferential step) formed on the inner circumferential surface of the high-pressure side slide valve body 15A on right-end side and a step (outer circumferential step) formed on the outer circumferential surface of the convex portion 15b of the low-pressure side slide valve body 15B. The O-ring <NUM> is arranged between the high-pressure side U-turn path 16A and the main valve chamber <NUM>. Note that, although the high-pressure side slide valve body 15A includes an outer brim 15c to improve operation stability thereof as illustrated in <FIG>, the outer brim 15c may not be provided as illustrated in <FIG>, etc..

The O-ring <NUM> seals the high-pressure side U-turn path 16A and the main valve chamber <NUM>. Fluids (refrigerants) with high pressure is introduced into an inner portion of the O-ring <NUM> from the port (high-pressure port at discharge side) pA via the high-pressure side U-turn path 16A. Note that sealing members such as lip seals may be used instead of the O-ring <NUM>, and shapes of the O-ring <NUM> and other sealing members are not limited to rings and may be quadrilaterals.

As it is apparent from <FIG>, <FIG> and <FIG>, when viewing from the right-left direction (direction orthogonal to the first main valve seat <NUM>), an area Sb in the high-pressure side valve body 15A at the right-surface side of the high-pressure side valve body 15A is larger than an area Sa in the high-pressure side valve body 15A at the left-surface side of the high-pressure side valve body 15A. The area Sb is a projected area inside a diameter of the O-ring <NUM> relative to plane perpendicular to the right-left direction.

The area Sa is a projected area (area substantially the same as a projected are of the inner brim 15a) inside the annular sealing surface at the first main valve seat <NUM>-side relative to the plane perpendicular to the right-left direction (direction orthogonal to the valve seating surface of the first main valve seat <NUM>), and is an area which pressure in the left direction is not applied to (the right side of) the high-pressure side slide valve body 15A. In the present embodiment, since a sliding surface of the bridge <NUM> is a sealing surface, a shape of the area Sa is annular, and the area Sa becomes an interior of the inner brim 15a when the bridge <NUM> is floated from the valve seating surface.

That is, differential pressure that acts on the high-pressure side slide valve body 15A is produced due to a difference (Sb-Sa) in the areas of the high-pressure side slide valve body 15A at the right-surface side and the left-surface side. By this differential pressure, (the annular sealing surface of) a left surface of the high-pressure side slide valve body 15A is pressed against the valve seating surface of the first main valve seat <NUM>. That is, the left surface of the high-pressure side slide valve body 15A is pressed against the first main valve seat <NUM>.

Furthermore, when a refrigerant with high pressure is introduced into the high-pressure side U-turn path 16A via the port (high-pressure port at discharge side) pA, (the annular sealing surface of) a right surface of the low-pressure side slide valve body 15B is pressed against the valve seating surface of the second main valve seat <NUM> by the pressure applied from the refrigerant with high pressure in the high-pressure side U-turn path 16A. In detail, the right surface of the low-pressure side slide valve body 15B is pressed against the valve seating surface of the second main valve seat <NUM> by the differential pressure between the pressure applied from the refrigerant with high pressure flowing through the high-pressure side U-turn path 16A and the pressure applied from the refrigerant with low pressure flowing through the low-pressure side U-turn path 16B.

Note that, a biasing component to bias the high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B in the opposite direction (direction to be separate) to each other may be arrange between the high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B, for example, outside the O-ring <NUM>.

The biasing component may be a ring-shaped leaf spring and compression coil spring, etc. By the biasing force of the biasing component, (the annular sealing surface of) a left surface of the high-pressure side slide valve body 15A can be pressure-welded (pressed) against the valve seating surface of the first main valve seat <NUM>.

Note that, in the present example, a reinforcement pin 15d for shape retention is bridged in the front-back direction at substantially center of the low-pressure side U-turn path 16B of the low-pressure side slide valve body 15B (refer <FIG>, <FIG>, and <FIG>). Furthermore, in the present example, a depressed surface 15e is formed on the upper and lower surfaces of (the high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B configuring) the main valve body <NUM>. A supporting plate 25c of (connectors 25A and 25B of) a connector <NUM> described later is fit into the depressed surface 15e with slight gaps in the right-left direction.

The high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B are configured to move integrally in the axial direction O such that the main valve body <NUM> would selectively be at a cooling position (upper end position) in <FIG> and a heating position (lower end position) in <FIG>. As illustrated in <FIG>, the main valve body <NUM> at the cooling position (upper end position) opens the port pF and communicates the ports pB and pA via the high-pressure side U-turn path 16A of the high-pressure side slide valve body 15A. Furthermore, the main valve body <NUM> opens the port pE and communicates the ports pC and pD via the low-pressure side U-turn path 16B of the low-pressure side slide valve body 15B.

As illustrated in <FIG>, the main valve body <NUM> at the heating position (lower end position) opens the port pB and communicates the ports pA and pF via the high-pressure side U-turn path 16A of the high-pressure side slide valve body 15A. Furthermore, the main valve body <NUM> opens the port pC and communicates the ports pD and pE via the low-pressure side U-turn path 16B of the low-pressure side slide valve body 15B.

In the main valve body <NUM>, the high-pressure side slide valve body 15A is located right above the two ports (pB and pA, or pA and pF) among three ports except during the movement. The low-pressure side slide valve body 15B is located right above the two ports (pC and pD, or pD and pE) among three ports except during the movement. The high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B are pressed toward right and left respectively and are pressure-welded to the valve seating surfaces of the first main valve seat <NUM> and the second main valve seat <NUM> respectively by the pressure from the refrigerant with high pressure introduced in the high-pressure side U-turn path 16A inside the main valve body <NUM>.

The first piston <NUM> and the second piston <NUM> are connected to be integrally movable by the connector <NUM>. The high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B of the main valve body <NUM> are fit to and supported by the connector <NUM> in a state in which the high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B are slightly freely slidable in the right-left direction and are not movable in the front-back direction.

In the present example, the connector <NUM> is formed of a pair of plates having same dimensions and same shapes made by, for example, press molding. The plates of the connector <NUM> are arranged along the right-left direction (direction orthogonal to the valve seating surface of the first main valve seat <NUM> and second main valve seat <NUM>), that is, in parallel with the plane orthogonal to the valve seating surface. Furthermore, in the connector <NUM>, the pair of plates are arranged to face each other in the front-back direction, and sandwich and hold the main valve body <NUM> therebetween in the front-back direction. Hereinafter, a plate arranged in front of the main valve body <NUM> is called the connector 25A, and a plate arranged on the back of the main valve body <NUM> is called the connector 25B.

In detail, as it is clear from <FIG>, <FIG>, <FIG> and <FIG>, the connectors 25A and 25B are configured of longitudinally rectangular (here, having same widths across entire length) plates which is symmetric relative to the center line (symmetry line) extending in the front-back direction from the center of the plates. The supporting member 25c is formed at substantially the center (in the vertical direction) of the connectors 25A and 25B to integrally movably engage and support a front-side portion or a back-side portion of the main valve body <NUM> in the axial direction O. As illustrated in <FIG> and <FIG>, the supporting member 25c forms a shape along an outer circumference (front side, up side, and down side, or back side, up side, and down side) of the main valve body <NUM>, that is, substantially U-shape in cross section. Width of the supporting member 25c in the right-left direction is set to be slightly smaller than the width of the depressed surface 15e provided on the upper and lower surfaces of the main valve body <NUM>.

Connection members 25a extending to the first piston <NUM> or the second piston <NUM> are connected above or below the supporting member 25c in the connectors 25A and 25B. The connection members 25a are formed in step-shape or clank-shape by bending, etc. An offset plate 25aa and a contact plate 25ab are provided to the connection portion 25a from the supporting member 25c-side.

The offset plate 25aa of the connection portion 25a of the front-side connector 25A is arranged at the front side of the axis O, in particular, at a position offset to the front side of the six ports pA to pF opened on the valve seating surface of the first main valve seat <NUM> and the second main valve seat <NUM> (in other word, a position offset forwardly from the six ports pA to pF) when viewed from the right-left direction.

Furthermore, the offset plate 25aa of the connection portion 25a of the back-side connector 25B is arranged at the back side of the axis O, in particular, at a position offset to the back side of the six ports pA to pF opened on the valve seating surface of the first main valve seat <NUM> and the second main valve seat <NUM> (in other word, a position offset backwardly from the six ports pA to pF) when viewed from the right-left direction.

That is, in the present example, the offset plates 25aa of the connection portions 25a in the pair of connectors 25A and 25B are positioned to not obstruct a flow of the refrigerant flowing through the ports pB, pC, pE and pF opened on the valve seating surface of the first main valve seat <NUM> and the second main valve seat <NUM> (in particular, refer <FIG>). In detail, in the cooling position (upper end position) illustrated in <FIG>, the offset plate 25aa is positioned to not obstruct the flow of refrigerant in the ports pF and pE positioned at the lower side, and in the heating position (lower end position) illustrated in <FIG>, the offset plate 25aa is positioned to not obstruct the flow of refrigerant in the ports pB and pC positioned at the upper side.

Furthermore, the contact plate 25ab of the connection member 25a in the connector 25A is in contact with the contact plate 25ab of the connection member 25a in the connector 25B. The contacts plates 25ab are portions close to the first piston <NUM> or the second piston <NUM> and are portions that do not overlap with the ports pA to pF opened on the valve seating surface of the first main valve seat <NUM> and the second main valve seat <NUM>. Note that, for example, recesses and protrusions (matching portions), may be provided in the contact plates 25ab to match the facing connectors 25A and 25B to each other, in view of assemblability described later.

Attaching legs 25b are provided on upper and lower ends of the connection members 25a of the connectors 25A and 25B. The attaching legs 25b are bent substantially <NUM> degrees toward the opposite side to the facing connectors 25A and 25B (direction to which the supporting member 25c with uneven surface). Screw holes <NUM> are provided in the attaching legs 25b to insert bolts <NUM>. As illustrated in <FIG>, the bolts <NUM> are provided to connect the connectors 25A and 25B to the first piston <NUM> or the second piston <NUM>.

As described above, in the present example, since the connectors 25A and 25B are configured of plates having same dimensions and same shapes, two connecters 25A and 25B can be arranged to face each other in the front-back direction. Furthermore, the contact plates 25ab of the connection portions 25a of the connectors 25A and 25B can be assembles and arranged to abut with each other reversely (in detail, up-side down to each other).

At this time, by respectively arranging the high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B of the main valve body <NUM> from right-left direction between the supporting members 25c of the connectors 25A and 25B (in the substantially rectangular shape), the high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B may be fit to the connectors <NUM> in a state slightly freely slidable in the right-left direction and not movable in the front-back direction (in particular, refer <FIG>).

The main valve body <NUM> fit to and supported by the connectors 25A and 25B is presses and moved to an upper portion or a lower portion of the supporting member 25c with U-shape in cross section in the connectors 25A and 25B along with reciprocal movement of the first piston <NUM> and the second piston <NUM>. That is, the upper and lower surface of the high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B are pressed.

The pressed and moved main valve body <NUM> reciprocates between the cooling position (upper end position) and the heating position (lower end position). Note that, in the present example, although the connectors 25A and 25B are configured of the pair of plates having same dimensions and same shapes (connection plates 25A and 25B), the connector <NUM> may be configured of one plate, for example.

As illustrated in <FIG> and <FIG>, a four-way pilot valve <NUM> as a pilot valve has a valve casing <NUM>, and an attractor <NUM>, a compression coil spring <NUM>, and a plunger <NUM> are arranged linearly from the base-side in this order. The valve casing <NUM> is formed of a cylindrical straight pipe to which an electromagnetic coil <NUM> is fit and fixed on an outer circumference thereof on the base side (left end side). A left end of the valve casing is joined to a brim (outer circumferential terrace portion) of the attractor <NUM> by welding so as to be sealed, and the attractor <NUM> is fastened to a cover casing 91A covering the outer circumference of the electromagnetic coil <NUM> for current excitation by a bolt 92B.

On the other hand, a lid <NUM> with filters is airtightly attached to a right-end opening of the valve casing <NUM> by welding, brazing, and fastening, etc. The lid <NUM> has a thin tube insertion opening to introduce the refrigerant with high pressure. A region surrounded by the lid <NUM>, the plunger <NUM> and the valve casing <NUM> is a valve chamber <NUM>. The refrigerant with high temperature and high pressure is introduced into the valve chamber <NUM> from the port pA via a high-pressure thin tube #a inserted airtightly into the thin tube insertion opening of the lid <NUM>.

Furthermore, a valve seat <NUM>, which an inner end surface thereof is a valve seating surface, is airtightly joined between the plunger <NUM> ad the lid <NUM> of the valve casing <NUM> by brazing, etc. Three ports are opened and aligned horizontally at even intervals on the valve seating surface (inner end surface) of the valve seat <NUM>, and thin tubes #b, #c and #d are connected to the respective ports. The thin tube #b is connected to the first operation chamber <NUM> of the flow path valve main body <NUM>, the thin tube #c is connected to the port pD, and the thin tube #d is connected to the second operation chamber <NUM> of the flow path valve main body <NUM>.

The plunger <NUM> is basically a cylinder, is arranged opposite to the attractor, and is arranged freely slidably in the axial direction (direction along the center line of the valve casing <NUM>) inside the valve casing <NUM>. A valve body <NUM> is a component to switch communications between the ports by selectively communicating the adjacent ports among three ports opened on the valve seating surface of the valve seat <NUM>. The valve body <NUM> slides in a state in contact with the valve seating surface of the valve seat <NUM> along with the right-left movement of the plunger <NUM> on the valve seating surface of the valve seat <NUM>.

The compression coil spring <NUM> is arranged and is compressed between the attractor <NUM> and the plunger <NUM> and biases the plunger <NUM> in the direction away from the attractor <NUM> (rightward in <FIG> and <FIG>), and in the present example, a left end of the valve seat <NUM> works as a stopper that prevents the rightward movement of the plunger <NUM>. Note that this stopper may be achieved by applying other components.

In the above-described four-way pilot valve <NUM>, as illustrated in <FIG>, when current to the electromagnetic coil <NUM> is OFF, the plunger <NUM> is pushed to a position at which the right end thereof contacts the valve seat <NUM> by biasing force of the compression spring coil <NUM>, such that the valve body <NUM> communicates the adjacent ports among three ports opened on the valve seating surface of the valve seat <NUM>.

When the current to the electromagnetic coil <NUM> is OFF, fluids with high pressure flowing into the port (high-pressure port at discharge side) pA are introduced to the second operation chamber <NUM> via the high-pressure thin tube #a, the valve chamber <NUM>, the thin tube #d, and the port p12. Furthermore, the fluids with high pressure in the first operation chamber <NUM> are ejected from the port (low-pressure port at suction side) pD via the port p11, the thin tube #b, the port b, a convex portion 94a, the port c, and the thin tube #c.

In contrast, as illustrated in <FIG>, when the current to the electromagnetic coil <NUM> is ON, the plunger <NUM> is pulled to a position at which the left end thereof contacts the attractor <NUM> by attraction force of the attractor <NUM> (against biasing force of the compression coil spring <NUM>), such that the valve body <NUM> is moved. At this time, fluids with high pressure flowing into the port (high-pressure port at discharge side) pA are introduced to the first operation chamber <NUM> via the high-pressure thin tube #a, the valve chamber <NUM>, the thin tube #b, and the port p11. Furthermore, the fluids with high pressure in the second operation chamber <NUM> are ejected from the port (low-pressure port at suction side) pD via the port p12, the thin tube #d, and the thin tube #c.

As described above, when current to the electromagnetic coil <NUM> is OFF, the main valve body <NUM> of the flow path valve main body <NUM> moves from the heating position to the cooling position to switch the flow path. Furthermore, when the current to the electromagnetic coil <NUM> is ON, the main valve body <NUM> of the flow path valve main body <NUM> moves from the cooling position to the heating position to switch the flow path.

By this, in the flow path switching valve <NUM> of the present embodiment, by switching ON/OFF of the current to the electromagnetic four-way pilot valve <NUM>, the main valve body <NUM> can be moved inside the main valve chamber <NUM> by utilizing the differential pressure between the fluid with high pressure (fluid flowing in the port pA that is the high-pressure portion) and the fluid with low pressure (fluid flowing in the port pD that is the low-pressure portion). By this, communications among six ports provided in the main valve housing <NUM> in total can be switched. Thus, the heat-pump type air conditioning system <NUM> illustrated in <FIG> and <FIG> can be switched from the heating operation to the cooling operation and from the cooling operation to the heating operation.

Actions of the flow path valve main body <NUM> when the heat-pump type air conditioning system <NUM> is switched from the heating operation to the cooling operation and from the cooling operation to the heating operation are described. As illustrated in <FIG>, when the valve main body <NUM> arranged inside the main valve housing <NUM> is at the heating position (lower end position), the second operation chamber <NUM> is communicated with the port pA that is the high-pressure port at discharge side via the four-way pilot valve <NUM>. Furthermore, the first operation chamber <NUM> is communicated with the port pD that is the low-pressure port at suction side.

By this, refrigerants with high temperature and high pressure are introduced into the second operation chamber <NUM>, while refrigerants with high pressure is ejected from the first operation chamber <NUM>. Accordingly, as illustrated in <FIG>, in the main valve chamber <NUM>, the pressure inside the second operation chamber <NUM> becomes higher than the pressure in the first operation chamber <NUM>, and the first piston <NUM>, the second piston <NUM>, and the main valve body <NUM> moves upward and the connector <NUM> contacts and is engaged with the upper connection plate 11d, so that the main valve body <NUM> is positioned at the cooling position (upper end position).

As a result, the ports pA and pD are communicated with each other via the high-pressure side U-turn path 16A, the ports pC and pD are communicated with each other via the low-pressure side U-turn path 16B, and the ports pE and pF are communicated with each other via the main valve chamber <NUM>. By this, the heat-pump type air conditioning system <NUM> performs the cooling operation.

Meanwhile, when the valve main body <NUM> is at the cooling position (upper end position), the first operation chamber <NUM> is communicated with the port pA that is the high-pressure port at discharge side via the four-way pilot valve <NUM>. Furthermore, the second operation chamber <NUM> is communicated with the port pD that is the low-pressure port at suction side. By this, refrigerants with high temperature and high pressure are introduced into the first operation chamber <NUM>, while refrigerants with high pressure is ejected from the second operation chamber <NUM>. Accordingly, as illustrated in <FIG>, in the main valve chamber <NUM>, the pressure inside the first operation chamber <NUM> becomes higher than the pressure in the second operation chamber <NUM>, and the first piston <NUM>, the second piston <NUM>, and the main valve body <NUM> moves downward and the connector <NUM> contacts and is engaged with the lower connection plate 11e, so that the main valve body <NUM> is positioned at the heating position (lower end position).

As a result, the ports pA and pF are communicated with each other via the high-pressure side U-turn path 16A, the ports pE and pD are communicated with each other via the low-pressure side U-turn path 16B, and the ports pC and pB are communicated with each other via the main valve chamber <NUM>. By this, the heat-pump type air conditioning system <NUM> performs the heating operation.

As understood from the above descriptions, the flow path switching valve <NUM> according to the first embodiment includes the tubular main valve housing <NUM> defining the main valve chamber <NUM>, and the slide-type main valve body <NUM> arranged movably in an axial direction and in the main valve chamber <NUM>, in which the main valve chamber <NUM> has three ports opened and aligned in the axial direction and has other three ports opened and aligned in the axial direction at the opposite side to the three ports across the axis, the main valve body <NUM> has the tubular high-pressure side slide valve body 15A and the low-pressure side valve body 15B freely slidably fit to the inner side of the high-pressure side slide valve body 15A, and the bridge <NUM>, which connects the inner circumferential surfaces of the high-pressure side slide valve body 15A facing each other in the direction orthogonal to the axial direction of the main valve chamber <NUM>, is provided on the inner circumferential surfaces.

As described above, in the flow path switching valve <NUM> according to the first embodiment, since the bridge <NUM> is provided on the inner circumferential surfaces of the high-pressure side slide valve body facing each other in the direction orthogonal to the axial direction of the main valve chamber <NUM>, rigidity of the high-pressure side slide valve body 15A is improved. Therefore, the deformation amount of the high-pressure side slide valve body 15A which rigidity thereof was improved by providing the bridge <NUM> can be suppressed to little even if pressure from fluids with high pressure is applied to the inner circumferential surface of the high-pressure side slide valve body 15A such that the tip side of the high-pressure side slide valve body 15A tends to expand outwardly. Therefore, the deformation of the sealing surface of the high-pressure side slide valve body 15A can be suppressed, the sealing effect can be improved, and valve leakage of the main valve body <NUM> can be prevented. As a result, further improvement of the efficiency of the heat-pump type air conditioning system <NUM> can be achieved.

Furthermore, in the flow path switching valve <NUM> according to the first embodiment, since the bridge <NUM> is provided in the base portion of the high-pressure side slide valve body 15A, rigidity at a portion close to the sealing surface of the high-pressure side slide valve body 15A is improved. Therefore, the deformation of the sealing surface can be suppressed efficiently, the sealing effect is improved, and valve leakage of the main valve body <NUM> can be prevented.

In addition, the bridge <NUM> is formed of the end surface sandwiched by circular arcs of two openings only by providing the two openings which are respectively communicated with adjacent two ports provided in the end surface of the high-pressure side slide valve body 15A. Therefore, the bridge <NUM> does not inhibit a flow of fluid with high pressure passing through the ports. Accordingly, refrigerants with high pressure can smoothly flow via the high-pressure side U-turn path 16A, and pressure loss can be reduced.

Moreover, in the flow path switching valve <NUM> according to the first embodiment, by moving the main valve body <NUM> inside the main valve chamber <NUM>, a plurality of communication state, in which two ports among three ports are selectively communicated via the high-pressure side U-turn path 16A, two ports among another three ports are selectively communicated via the low-pressure side U-turn path 16B, and the other one port among three ports and the other one port among another three ports may be selectively communicated via the main valve housing <NUM>, may be selected.

Therefore, in the first embodiment, the first main valve seat <NUM> and the second main valve seat <NUM> to which ports are provided, and the main valve body <NUM> can be shorter in the axial direction in comparison with the flow path switching valve using conventional slide-type main valve bodies. Accordingly, surface accuracy and flatness of the valve seating surface of the first main valve seat <NUM> and the second main valve seat <NUM> and the sealing surface of the main valve body <NUM> can be easily ensured. As a result, valve leakage of the flow path switching valve <NUM> can be prevented, refrigerants with high pressure can be stably flown in the high-pressure side U-turn path 16A, and pressure loss can be reduced.

Additionally, in the present embodiment, since fluids (for example, refrigerant with low pressure) flowing inside the flow path valve main body <NUM> flow via the low-pressure side U-turn path 16B and fluids (for example, refrigerants with middle pressure) flow in the right-left direction (linearly) inside the main valve chamber, pressure loss can be reduced. In addition, in the flow path switching valve <NUM>, since the O-ring <NUM> that is an annular sealing member is provided between the high-pressure side slide valve body 15A and the convex portion 15b of the low-pressure side slide valve body 15B, valve leakage can be further surely suppressed.

In addition to the above descriptions, when the flow path switching valve <NUM> according to the present embodiment is used in environments where refrigerants with high temperature and high pressure and refrigerants with low temperature and low pressure flow, such as the heat-pump type air conditioning systems, the high-pressure side U-turn path 16A through which refrigerants with high temperature and high pressure flows and the low-pressure side U-turn path 16B through which refrigerants with low temperature and low pressure flows may be largely separated, for example, without the metal main valve seat. Therefore, heat exchange amount (that is, heat loss) between refrigerants with high temperature and high pressure and refrigerants with low temperature and low pressure can be significantly reduced when compared with the conventional heat-pump type air conditioning systems in which refrigerants with high temperature and high pressure and refrigerants with low temperature and low pressure flow in a state close to each other via the metal main valve seat. As a result, efficiency of the heat-pump type air conditioning system <NUM> can be further improved.

Furthermore, in the main valve body <NUM> of the flow path switching valve <NUM> according to the present embodiment, the high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B are arranged back-to-back to each other so that the high-pressure side U-turn path 16A and the low-pressure side slide valve body 16B face opposite side to each other. Therefore, fluids with high pressure introduced between the high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B push the high-pressure side slide valve body 15A and the low-pressure side slide valve body 15B to the first main valve seat <NUM> and the second main valve seat <NUM>, respectively.

Also, in high-pressure side slide valve body 15A according to the first embodiment, since the bridge <NUM> is provided in the base portion, pressure of fluids with high pressure is applied to the bridge <NUM>, and the left surface of the high-pressure side slide valve body 15A is strongly pushed against the first main valve seat <NUM>. By such an action of fluid with high pressure, sealing effect of the main valve body <NUM> is improved, and the valve leakage thereof can be suppressed. In addition, since heat loss between refrigerants with high temperature and high pressure and refrigerants with low temperature and low pressure can be reduced, efficiency of the heat-pump type air conditioning system <NUM> can be further improved.

Basic configurations of a flow path switching valve <NUM> according to a second embodiment is the same as that of the above first embodiment. Therefore, same components are labeled by same signs and descriptions thereof are omitted, and only differences are described.

As illustrated in <FIG>, representing the present invention, in the flow path switching valve <NUM> according to the second embodiment a curved portion 19a having a dome-shape in cross section which is curved and protruding toward the low-pressure side slide valve body 15B is formed in the bridge <NUM>.

The flow path switching valve <NUM> according to the second embodiment has the following specific actions and effects. That is, in the second embodiment, the curved portion 19a is formed in the bridge <NUM>. The curved portion 19a forms a dome-shape in cross section which is curved and protruding toward the low-pressure side slide valve body 15B. Therefore, the bridge <NUM> has an inclined surface curving along the shape of the high-pressure side U-turn path 16A. Accordingly, the bridge <NUM> does not inhibit a flow of fluid with high pressure introduced to he high-pressure side U-turn path 16A. By this, refrigerants with high pressure can smoothly flow via the high-pressure side U-turn path 16A, and pressure loss can be reduced.

Above-described embodiments are presented as examples of embodiments of the present disclosure, and embodiments of the present disclosure can be implemented in other various forms. For example, in the first and second embodiments, although the bridge <NUM> is formed integrally with the high-pressure side slide valve body 15A by providing two openings which are respectively communicated with adjacent two ports in the end surface of the high-pressure side slide valve body 15A, it is not limited thereto.

For example, a member that configures the bridge <NUM> may be separate from the high-pressure side slide valve body 15A, and the member that configures the bridge <NUM> may be attached to the high-pressure side slide valve body 15A. Configurations, shapes, and dimensions of the bridge <NUM> may be changed as appropriate, and the bridge <NUM> may be formed by a plurality of members.

Claim 1:
A flow path switching valve (<NUM>) comprising:
a main valve housing (<NUM>) defining a main valve chamber (<NUM>); and
a slide-type main valve body (<NUM>) arranged movably in an axial direction (O) and in the main valve chamber (<NUM>),
wherein:
the main valve chamber (<NUM>) has three ports (pA, pB, pF) opened and aligned in the axial direction (O) and has other three ports (pB, pC, pD) opened and aligned in the axial direction (O) at the opposite side to the three ports (pA, pB, pF) across an axis, and the ports communicated with each other are switched by moving the main valve body (<NUM>) inside the main valve chamber (<NUM>),
the main valve body (<NUM>) has a tubular high-pressure side slide valve body (15A) and a low-pressure side valve body (15B) freely slidably fit to an inner side of the high-pressure side slide valve body (15A),
a bridge (<NUM>), which connects inner circumferential surfaces of the high-pressure side slide valve body (15A) facing each other in a direction orthogonal to the axial direction (O), is provided on the inner circumferential surfaces,
a convex portion (15b) protruding toward a high-pressure side slide valve body-side (15A) is provided in the low-pressure side slide valve body (15B), characterized in that
a high-pressure side U-turn path (16A) to which fluid with high pressure is introduced is defined in a space surrounded by the convex portion (15b) and the inner circumferential surface of the high-pressure side slide valve body (15A),
a curved portion (19a) having a dome-shape in cross section which is curved and protruding toward the low-pressure side slide valve body (15B) is formed in the bridge (<NUM>).