Evaporator unit having tank provided with ejector nozzle

In an evaporator unit for a refrigerant cycle device, an evaporator is connected to an ejector to evaporate refrigerant to be drawn into a refrigerant suction port of the ejector or the refrigerant flowing out of the outlet of the ejector. The evaporator includes a plurality of tubes in which the refrigerant flows, and a tank configured to distribute the refrigerant into the tubes or to collect the refrigerant from the tubes. The ejector is located in the tank, and the nozzle portion is brazed to the tank to be fixed into the tank. The tank may be a header tank directly connected to the tubes or may be a separate tank separated from the header tank.

CROSS REFERENCE TO RELATED APPLICATION

This application is based on Japanese Patent Applications No. 2007-276241 filed on Oct. 24, 2007, and No. 2008-193153 filed on Jul. 28, 2008, the contents of which are incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to an evaporator unit for a refrigerant cycle device with an ejector.

BACKGROUND OF THE INVENTION

JP-A-2007-192465 (corresponding to US 2007/0163294 A1) proposes an evaporator unit for a refrigerant cycle device with an ejector. In the evaporator unit, the ejector having a refrigerant decompressing function and a refrigerant circulating function is located inside a tank of an evaporator so that the ejector and the evaporator are integrated. Thus, the ejector and the evaporator can be mounted as an integrated unit, thereby improving a mounting performance of the refrigerant cycle device with the ejector.

In the evaporator unit, after an evaporator body is integrally brazed, the ejector is assembled to the evaporator body. Therefore, the productivity of the evaporator unit may be deteriorated, and the manufacturing cost of the evaporator unit may be increased. Furthermore, the ejector is difficult to be used for evaporators with different widths (i.e., different dimensions in a tank longitudinal direction), thereby reducing the compatibility of the ejector relative to the evaporators with different widths.

SUMMARY OF THE INVENTION

In view of the foregoing problems, it is an object of the present invention to improve the productivity of an evaporator unit while reducing the manufacturing cost of the evaporator unit.

It is another object of the present invention to improve the compatibility of an ejector relative to evaporators with different widths.

According to an aspect of the present invention, an evaporator unit includes an elector and an evaporator. The ejector has a nozzle portion configured to decompress refrigerant, and a refrigerant suction port from which the refrigerant is drawn by a high-speed refrigerant flow jetted from the nozzle portion. The refrigerant jetted from the nozzle portion and the refrigerant drawn from the refrigerant suction port are mixed and discharged from an outlet of the ejector. The evaporator is connected to the ejector to evaporate the refrigerant to be drawn into the refrigerant suction port or the refrigerant flowing out of the outlet of the ejector. Furthermore, the evaporator includes a plurality of tubes in which the refrigerant flows, and a tank configured to distribute the refrigerant into the tubes or to collect the refrigerant from the tubes. In addition, the ejector is located in the tank, and the nozzle portion is brazed to the tank to be fixed into the tank. Accordingly, the assemble work of the evaporator unit can be made simple as compared with a case where the nozzle portion is assembled to the evaporator after the evaporator is brazed. Therefore, the productivity of the evaporator unit can be improved while the manufacturing cost of the evaporator unit can be reduced.

For example, a part of the nozzle portion may be brazed to the tank. As an example, the nozzle portion may have substantially a cylindrical shape having an outer peripheral surface. In this case, the nozzle portion may be brazed to the tank at least on a part of the outer peripheral surface.

The evaporator unit may be provided with a suction refrigerant passage, provided at a radial outside of the nozzle portion, through which the refrigerant drawn from the refrigerant suction port flows. In this case, the outer peripheral surface of the nozzle portion is brazed to the tank at a portion except for the suction refrigerant passage.

At least one of the nozzle portion and the tank may be formed by a clad material on which a brazing material is covered. Alternatively, the nozzle portion may be provided with a temporal fixing portion configured to be temporally fixed to the tank.

The nozzle portion may be partially brazed to the tank at plural positions except for a refrigerant inlet and a refrigerant outlet of the nozzle portion.

The evaporator unit may be further provided with a nozzle support portion located in the tank and protruding from an inner wall surface of the tank to the outer peripheral surface of the nozzle portion to support the nozzle portion. In this case, the nozzle portion and the nozzle support portion are brazed to be fixed to each other, and at least one of the plural positions is a brazing portion between the nozzle portion and the nozzle support portion.

In the evaporator unit, the tank may be configured to extend in a tank longitudinal direction and to have therein first and second spaces partitioned from each other in the tank longitudinal direction, such that the first space of the tank is configured to distribute the refrigerant into the tubes, and the second space of the tank is configured to collect the refrigerant from the tubes. In this case, the refrigerant inlet of the nozzle portion is located in the first space, and the refrigerant outlet of the nozzle portion is located in the second space. Furthermore, the evaporator unit includes a refrigerant inlet provided at an end portion of the tank on a side of the first space in the tank longitudinal direction, and a nozzle inlet pipe located in the first space of the tank. The refrigerant inlet of the nozzle portion communicates with the refrigerant inlet of the end portion of the tank through the nozzle inlet pipe. Furthermore, one of the nozzle portion and the nozzle inlet pipe can be inserted into the other one of the nozzle portion and the nozzle inlet pipe. Accordingly, the compatibility of an ejector relative to evaporators with different widths can be improved.

As an example, the nozzle portion is inserted into the nozzle inlet pipe to have an insertion portion. In this case, the insertion portion of the nozzle portion is brazed to an end portion of the nozzle inlet pipe.

According to another aspect of the present invention, an evaporator unit includes an ejector and an evaporator. The ejector has a nozzle portion configured to decompress refrigerant, and a refrigerant suction port from which refrigerant is drawn by a high-speed refrigerant flow jetted from the nozzle portion. The refrigerant jetted from the nozzle portion and the refrigerant drawn from the refrigerant suction port are mixed in the ejector and discharged from an outlet of the ejector. The evaporator is connected to the ejector to evaporate the refrigerant to be drawn into the refrigerant suction port or the refrigerant flowing out of the outlet of the ejector. Furthermore, the evaporator has a plurality of tubes in which the refrigerant flows, and a tank extending in a tank longitudinal direction that is in parallel with an arrangement direction of the tubes to distribute the refrigerant into the tubes or to collect the refrigerant from the tubes. In the evaporator unit, the tank is configured to have therein first and second spaces partitioned from each other in the tank longitudinal direction, the first space of the tank is configured to distribute the refrigerant into the tubes, the second space of the tank is configured to collect the refrigerant from the tubes, the nozzle portion has a refrigerant inlet positioned in the first space and a refrigerant outlet positioned in the second space, the tank has a refrigerant inlet on a side of the first space in the tank longitudinal direction, and the refrigerant inlet of the nozzle portion communicates with the refrigerant inlet of the tank via a nozzle inlet pipe located in the first space of the tank. Accordingly, by suitably adjusting or setting the length of the nozzle inlet pipe, the ejector can be used for various links of evaporators having different widths in the tank longitudinal direction. Thus, the compatibility of the ejector relative to evaporators with different widths can be improved.

For example, one of the nozzle portion and the nozzle inlet pipe may be inserted into the other one of the nozzle portion and the nozzle inlet pipe. In this case, the insertion length between the nozzle portion and the nozzle inlet pipe can be suitably adjusted.

The nozzle inlet pipe may have a hole from which a part of the refrigerant flowing into the nozzle inlet pipe from the refrigerant inlet of the tank flows into the first space. Alternatively, a plurality of the holes may be provided in the nozzle inlet pipe in the tank longitudinal direction. Generally, the hole is provided to configure a throttle in which the refrigerant is decompressed.

In the evaporator unit according to the above aspects of the present invention, the refrigerant suction port may be provided along an entire outer periphery of the nozzle portion in a circumferential direction.

According to another aspect of the present invention, an evaporator unit includes an ejector and an evaporator. The ejector has a nozzle portion configured to decompress refrigerant, and a refrigerant suction port from which refrigerant is drawn by a high-speed refrigerant flow jetted from the nozzle portion. The refrigerant jetted from the nozzle portion and the refrigerant drawn from the refrigerant suction port are mixed in the ejector and discharged from an outlet of the ejector. The evaporator is connected to the ejector to evaporate the refrigerant to be drawn into the refrigerant suction port or the refrigerant flowing out of the outlet of the ejector. Furthermore, the evaporator includes a plurality of tubes in which the refrigerant flows, and a header tank configured to distribute the refrigerant into the tubes or to collect the refrigerant from the tubes. In the evaporator unit, a separate tank is located to be partitioned from the header tank while contacting the header tank. In addition, the ejector is located in the separate tank outside the header tank, and the nozzle portion is brazed to the separate tank to be fixed into the separate tank. Accordingly, the productivity of the evaporator unit can be improved while the manufacturing cost of the evaporator unit can be reduced.

For example, the ejector may be configured in the separate tank to define a suction refrigerant passage at a radial outside of the nozzle portion between the nozzle portion and the separate tank, and the suction refrigerant passage is made to communicate with the refrigerant suction port such that the refrigerant drawn from the refrigerant suction port flows through the suction refrigerant passage. In this case, an outer peripheral surface of the nozzle portion is brazed to the separate tank at a portion except for the suction refrigerant passage.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Embodiment

A first embodiment of the present invention and modifications of the first embodiment will be described below with reference toFIGS. 1 to 5. In the present embodiment, an evaporator unit for an ejector refrigerant cycle device and an ejector refrigerant cycle device using the evaporator unit will be now described. For example, the evaporator unit is an ejector-equipped evaporator unit for a refrigerant cycle device.

The evaporator unit is connected to other components of the refrigerant cycle device, including a condenser (refrigerant cooler), a compressor, and the like, via piping. The evaporator unit of the present embodiment is used for application to an indoor equipment (i.e., evaporator) for cooling air. However, the evaporator unit may be used as an outdoor equipment in other examples.

In an ejector refrigerant cycle device10shown inFIG. 1, a compressor11for drawing and compressing refrigerant is driven by an engine for vehicle traveling (not shown) via an electromagnetic clutch11a, a belt, or the like. The ejector refrigerant cycle device10is a refrigerant cycle device with an ejector.

As the compressor11, may be used either a variable displacement compressor which can adjust a refrigerant discharge capability by a change in discharge capacity, or a fixed displacement compressor which can adjust a refrigerant discharge capability by changing an operating ratio of the compressor through engagement and disengagement of an electromagnetic clutch11a. If an electric compressor is used as the compressor11, the refrigerant discharge capability of the compressor11can be adjusted or regulated by adjustment of the number of revolutions of an electric motor.

A refrigerant radiator12is disposed on a refrigerant discharge side of the compressor11. The radiator12exchanges heat between the high-pressure refrigerant discharged from the compressor11and outside air (i.e., air outside a compartment of a vehicle) blown by a cooling fan (not shown) thereby to cool the high-pressure refrigerant.

As the refrigerant for the ejector refrigerant cycle device10in the present embodiment, is used a refrigerant whose high pressure does not exceed a critical pressure, such as a flon-based refrigerant, or a HC-based refrigerant, so as to form a vapor-compression subcritical cycle. Thus, the radiator12serves as a condenser for cooling and condensing the refrigerant in this embodiment.

A liquid receiver12ais provided at a refrigerant outlet side of the radiator12. The liquid receiver12ahas an elongated tank-like shape, as is known generally, and constitutes a vapor-liquid separator for separating the refrigerant into vapor and liquid phases to store therein an excessive liquid refrigerant of the refrigerant cycle. At a refrigerant outlet of the liquid receiver12a, the liquid refrigerant is derived from the lower part of the interior in the tank-like shape. In the present embodiment, the liquid receiver12ais integrally formed with the radiator12.

The radiator12may have a known structure which includes a first heat exchanger for condensation positioned on the upstream side of a refrigerant flow, the liquid receiver12afor allowing the refrigerant introduced from the first heat exchanger for condensation and for separating the refrigerant into vapor and liquid phases, and a second heat exchanger for supercooling the saturated liquid refrigerant from the liquid receiver12a.

A thermal expansion valve13is disposed on an outlet side of the liquid receiver12a. The thermal expansion valve13is a decompression unit for decompressing the liquid refrigerant flowing from the liquid receiver12a, and includes a temperature sensing part13adisposed in a refrigerant suction passage of the compressor11.

The thermal expansion valve13detects a degree of superheat of the refrigerant at the compressor suction side based on the temperature and pressure of the suction side refrigerant of the compressor11, and adjusts an opening degree of the valve (refrigerant flow rate) such that the superheat degree of the refrigerant on the compressor suction side becomes a predetermined value which is preset, as is known generally. Therefore, the thermal expansion valve13adjusts a refrigerant flow amount such that the superheat degree of the refrigerant on the compressor suction side becomes the predetermined value.

An ejector14is disposed at a refrigerant outlet side of the thermal expansion valve13. The ejector14is decompression means for decompressing the refrigerant as well as refrigerant circulating means (kinetic vacuum pump) for circulating the refrigerant by a suction effect (entrainment effect) of the refrigerant flow ejected at high speed.

The ejector14includes a nozzle portion14afor further decompressing and expanding the refrigerant (the middle-pressure refrigerant from the expansion valve) by restricting a path area of the refrigerant having passed through the expansion valve13to a small level. A refrigerant suction port14bis provided in the ejector14in the same space as a refrigerant jet port of the nozzle portion14ato draw the vapor-phase refrigerant from a second evaporator18as described later.

A mixing portion14cis provided on a downstream side of the refrigerant flow of the nozzle portion14aand the refrigerant suction port14b, for mixing a high-speed refrigerant flow jetted from the nozzle portion14aand the refrigerant drawn from the refrigerant suction port14b.

A diffuser14dserving as a pressure-increasing portion is provided on a downstream side of the refrigerant flow of the mixing portion14cin the ejector14. The diffuser14dis formed in such a manner that a path area of the refrigerant is generally increased toward downstream from the mixing portion14c. The diffuser14dserves to increase the refrigerant pressure by decelerating the refrigerant flow, that is, to convert the speed energy of the refrigerant into the pressure energy.

A first evaporator15is connected to an outlet side of the diffuser14dof the ejector14. A refrigerant outlet side of the first evaporator15is connected to a refrigerant suction side of the compressor11.

On the other hand, a refrigerant branch passage16is provided to be branched from an inlet side of the nozzle portion14aof the ejector14. That is, the refrigerant branch passage16is branched at a position between the refrigerant outlet of the thermal expansion valve13and the refrigerant inlet of the nozzle portion14aof the ejector14. The downstream side of the refrigerant branch passage16is connected to the refrigerant suction port14bof the ejector14. A point Z ofFIG. 1indicates a branch portion of the refrigerant branch passage16.

In the refrigerant branch passage16, a throttle17is disposed to decompress the refrigerant passing therethrough. On the refrigerant flow downstream side away from the throttle17in the refrigerant branch passage16, the second evaporator18is disposed. The throttle17serves as a decompression unit which decompresses the refrigerant while performing a function of adjusting a refrigerant flow amount into the second evaporator18. More specifically, the throttle17can be constructed with a fixed throttle, such as a capillary tube, or an orifice.

In the first embodiment, the two evaporators15and18are incorporated into an integrated structure with an arrangement as described later. The two evaporators15and18are accommodated in an air conditioning case not shown, and the air (air to be cooled) is blown by a common electric blower19through an air passage formed in the air conditioning case in the direction of an arrow “A”, so that the blown air is cooled by the two evaporators15and18.

The cooled air by the two evaporators15and18is fed to a common space to be cooled (not shown). This causes the two evaporators15and18to cool the common space to be cooled. Among these two evaporators15and18, the first evaporator15connected to a main flow path on the downstream side of the ejector14is disposed on the upstream side (upwind side) of the air flow A, while the second evaporator18connected to the refrigerant suction port14bof the ejector14is disposed on the downstream side (downwind side) of the air flow A.

When the ejector refrigerant cycle device10of the present embodiment is used as a refrigeration cycle for a vehicle air conditioner, the space within a passenger compartment of the vehicle is the space to be cooled. When the ejector refrigerant cycle device10of the present embodiment is used for a refrigeration cycle for a freezer car, the space within the freezer and refrigerator of the freezer car is the space to be cooled.

In the present embodiment, the ejector14, the first and second evaporators15and18, and the throttle17are incorporated into one integrated unit20. Now, specific examples of the evaporator unit20will be described below in detail with reference toFIGS. 2 to 4.FIG. 2is a perspective view showing the integrated unit20having the first and second evaporators15and18and the ejector14.FIG. 3is a cross-sectional view of a tank portion of the integrated unit20, andFIG. 4is an enlarged sectional view showing a part of the tank portion of the integrated unit20.

First, an example of the integrated unit20including the two evaporators15and18and the ejector14will be explained below with reference toFIG. 2. In the present embodiment ofFIG. 2, the two evaporators15and18can be formed integrally into a completely single evaporator structure. Thus, the first evaporator15constitutes an upstream side area of the single evaporator structure in the direction of the air flow A, while the second evaporator18constitutes a downstream side area of the single evaporator structure in the direction of the air flow A.

In the example of the integrated unit20ofFIG. 2, a side of the tank portion where the ejector14is located is indicated as the top direction, a side of the tank portion where the ejector14is not located is indicated as the bottom direction, an upstream refrigerant side of the nozzle portion14aof the ejector14is indicated as the right direction, and a downstream refrigerant side of the diffuser14dof the ejector14is indicated as the left direction, when being viewed from an upstream air side of the integrated unit20as in the arrow A ofFIG. 2.

The evaporator unit20including the first evaporator15, the second evaporator18and the ejector14is made of a metal material such as aluminum having a heat conduction and a brazing property. All the components of the evaporator unit20can be integrally bonded by brazing or can be integrated by using a fastening member.

The first evaporator15and the second evaporator18have the same basic structure, and include heat exchange cores15aand18a, and header tanks15b,15c,18b, and18cpositioned on both upper and lower sides of the heat exchange cores15aand18a, respectively.

The heat exchanger cores15aand18arespectively include a plurality of tubes21extending in a tube longitudinal direction (e.g., vertically inFIG. 2). The tube21is a flat tube defining therein a refrigerant passage in which the refrigerant flows. One or more passages for allowing a heat-exchange medium, namely air to be cooled in the present embodiment, to pass therethrough are formed between these tubes21. Between these tubes21, fins22are disposed, so that the tubes21can be connected to the fins22. Each of the heat exchange cores15aand18ais constructed of a laminated structure of the tubes21and the fins22. These tubes21and fins22are alternately laminated in a lateral direction of the heat exchange cores15aand18a. In other embodiments, any appropriate structure without using the fins22in the heat exchange cores15aand18amay be employed.

InFIG. 2, only some of the fins22are shown, but in fact the fins22are disposed over the whole areas of the heat exchange cores15aand18a, and the laminated structure including the tubes21and the fins22is disposed over the whole areas of the heat exchange cores15aand18a. The blown air by the electric blower19is adapted to pass through voids (clearances) in the laminated structure of the tubes21and the fins22.

The tube21constitutes the refrigerant passage through which refrigerant flows, and is made of a flat tube having a flat cross-sectional shape in the air flow direction A. The fin22is a corrugated fin made by bending a thin plate in a wave-like shape, and is connected to a flat outer surface of the tube21to expand a heat transfer area of the air side.

The header tanks15band15care located, respectively, at top and bottom sides of the heat exchange core15a, and the header tanks18band18care located, respectively, at top and bottom sides of the heat exchange core18a. In the first embodiment, the ejector14is located in the upper header tank18b, as an example.

The header tanks15b,15c,18b,18care connected to end portions of the tubes21in the longitudinal direction to distribute the refrigerant into the tubes21and to collect the refrigerant from the tubes21.

The header tanks15b,15clocated on both the top and bottom sides of the first evaporator15have tube-fitting hole part (not shown), and both top and bottom end portions of the tubes21of the heat exchange core15aare inserted into and are bonded to the tube-fitting hole part, such that the both top and bottom end portions of the tubes21communicate with the inner space of the header tanks15b,15c.

Similarly, the header tanks18b,18clocated on both top and bottom sides of the second evaporator18have tube-fitting hole part (not shown), and both top and bottom end portions of the tubes21of the heat exchange core18aare inserted into and are bonded to the tube-fitting hole part, such that the both top and bottom end portions of the tubes21communicate with the inner space of the header tanks18b,18c.

The tubes21of the heat exchanger core15aand the tubes21of the heat exchanger core18aindependently constitute the respective refrigerant passages. The header tanks15band15con both upper and lower sides of the first evaporator15, and the header tanks18band18con both upper and lower sides of the second evaporator18independently constitute the respective refrigerant passage spaces.

Thus, the header tanks15b,15c,18b, and18cdisposed on both upper and lower sides serve to distribute the refrigerant to the respective tubes21of the heat exchange cores15aand18a, and to collect the refrigerant from the tubes21of the heat exchange cores15aand18a.

Since the two upper header tanks15band18bare adjacent to each other, the two upper header tanks15band18bcan be molded integrally to form an upper tank portion of the integrated unit20. The same can be made for the two lower header tanks15cand18cso as to form a lower tank portion of the integrated unit20. It is apparent that the two upper header tanks15band18bmay be molded independently as independent components, and that the same can be made for the two lower header tanks15cand18c.

A partition plate23is located in the upper header tank15bof the first evaporator15at a center portion in a tank longitudinal direction (e.g., left-right direction corresponding to the width direction of the evaporator unit), to partition an inner space of the upper header tank15binto a right space25and a left space26. The partition plate23can be brazed to an inner wall surface of the upper header tank15b. Similarly, a partition plate24is located in the upper header tank18bof the second evaporator18at a center portion in a tank longitudinal direction (e.g., left-right direction), to partition an inner space of the upper header tank18binto a right space27and a left space28. The partition plate24can be brazed to an inner wall surface of the upper header tank18b. Furthermore, as shown inFIG. 3, a nozzle support plate33is located in the right space27of the upper header tank18bto support the nozzle portion14aof the ejector14. In the present embodiment, the partition plate24and the nozzle support plate33are located to support the nozzle14aof the ejector14.

On the other hand, no partition plate is located in the lower header tanks15c,18cof the first and second evaporators15,18. Therefore, the inner space of the lower header tank15cof the first evaporator15is a single communicating space, and the inner space of the lower header tank18cof the second evaporator18is a single communicating space.

As shown inFIG. 2, a connection block29is brazed and fixed to a side surface portion of the upper header tanks15b,18b, positioned at one end side in the tank longitudinal direction (e.g., left-right direction). The connection block29is provided with a single refrigerant inlet30and a single refrigerant outlet31of the evaporator unit20shown inFIG. 1.

The refrigerant inlet30of the connection block29is connected to a refrigerant downstream side of the expansion valve13. In the evaporator unit20, the refrigerant inlet30of the connection block29communicates with the right space27of the upper header tank18b. The refrigerant outlet31of the connection block29communicating with the right space25of the upper header tank15bof the first evaporator15is connected to the refrigerant suction side of the compressor11.

The ejector14is located inside the upper header tank18bof the second evaporator18. In the ejector14of the first embodiment shown inFIG. 3, the nozzle portion14ais separated from the mixing portion14cwhile the mixing portion14cand the diffuser14dare integrally formed in the upper header tank18b.

The nozzle portion14ahas an outlet portion on a side of the jet port, and the outlet portion of the nozzle portion14ais inserted into an insertion hole of the partition plate24such that the nozzle portion14ais arranged in the upper header tank18bover the right space27and the left space28, as shown inFIG. 3. Thus, the refrigerant inlet of the nozzle portion14ais positioned in the right space27of the upper header tank18b, and the jet port of the nozzle portion14ais positioned in the left space28of the upper header tank18b.

The nozzle portion14aof the ejector14and the partition plate24are brazed to be air-tightly sealed and fixed to each other.FIG. 4schematically shows a brazing point B1between the nozzle portion14aand the partition plate24, a brazing point B2between the nozzle portion14aand a nozzle inlet pipe32, and a brazing point B3between the nozzle inlet pipe32and the nozzle support plate33.

As shown inFIG. 3, the mixing portion14cand the diffuser14dof the ejector14are entirely arranged in the left space28of the upper header tank18b. In the example ofFIG. 3, the suction port14bis constructed by the inlet side opening of the mixing portion14c. Therefore, the inlet side opening of the mixing portion is positioned coaxially with the nozzle portion14a, and is directly opened to the left space28of the upper header tank18b. The jet port of the nozzle portion14ais positioned close to the inlet side opening of the mixing portion14c.

Thus, the suction port14bis formed around an entire outside circumference of only a tip portion of the nozzle portion14a. The mixing portion14cis formed approximately into a cylindrical shape, and the diffuser14dis enlarged from the mixing portion14cin passage section such that the outlet of the diffuser14dis directly open to the left space26of the upper header tank15bof the first evaporator15.

The mixing portion14cand the diffuser14dcan be fixed to the upper header tank18bby using a suitable fastening member, or can be brazed to the upper header tank18b.FIG. 3shows one example of the shapes of the mixing portion14cand the diffuser14d. However, the shapes of the mixing portion14cand the diffuser14dcan be suitably changed without being limited to the shapes of the mixing portion14cand the diffuser14dshown inFIG. 3.

In the example ofFIG. 3, the refrigerant inlet30and the refrigerant outlet31are provided in the connection block29fixed to the right end surface of the upper header tanks18band15b. The refrigerant inlet of the nozzle portion14acommunicates with the refrigerant inlet30via the inner space of the nozzle inlet pipe32. An inlet side portion of the nozzle portion14ais inserted into one end portion of the nozzle inlet pipe32, and the other end portion of the nozzle inlet pipe32is inserted into a hole formed in a side wall (i.e., right side wall inFIG. 3) of the upper header tank18b.

The one end portion of the nozzle inlet pipe32is brazed to the nozzle portion14aso that an insertion portion (overlapped portion) between the one end portion of the nozzle inlet pipe32and the nozzle portion14acan be air tightly sealed. The nozzle portion14aand the nozzle inlet pipe32are brazed at least at about the point B2ofFIG. 4, for example. The point B2ofFIG. 4only schematically shows a brazing position between the nozzle portion14aand the nozzle inlet pipe32. The other end portion of the nozzle inlet pipe32opposite to the nozzle portion14ais brazed to the side wall surface of the upper header tank18bto be air-tightly sealed.

An insertion length L of the nozzle portion14ainto the nozzle inlet pipe32is set in accordance with the dimension of the right space27in the tank longitudinal direction (i.e., left-right direction inFIG. 3). Therefore, by adjusting the insertion length L of the nozzle portion14ainto the nozzle inlet pipe32, it is possible for the nozzle portion14ato be used for header tanks having different lengths in the tank longitudinal direction. That is, by adjusting the insertion length L of the nozzle portion14ainto the nozzle inlet pipe32, it is possible for the nozzle portion14ato be assembled to various kinds of the evaporators15,18having different width dimensions in the left-right direction.

In the present embodiment, the branch passage16and the throttle mechanism17are configured by using the nozzle inlet pipe32. As shown inFIG. 3, holes (orifices)32aare formed in a pipe wall of the nozzle inlet pipe32, so that a part of refrigerant flowing into the nozzle inlet pipe32from the refrigerant inlet30is decompressed while passing through the holes32aas the throttle17, and flows into the right space27outside of the nozzle inlet pipe32in the upper header tank18b.

Thus, the branch portion Z and a part of the branch passage16shown inFIG. 1are formed in the nozzle inlet pipe32, and the throttle17is constructed with the holes32a. In the example ofFIG. 3, two holes32aare arranged at two positions of the nozzle inlet pipe32in the tank longitudinal direction. However, one hole32amay be formed in the nozzle inlet pipe32as the throttle17, or plural holes32amore than two may be formed in the nozzle inlet pipe32aas the throttle17. The number of the holes32aand the arrangement positions thereof in the nozzle inlet pipe32may be suitably changed without being limited to the example ofFIG. 3.

The nozzle support plate33air-tightly connected to the outer peripheral surface of the nozzle inlet pipe32protrudes outwardly and is fixed by brazing to an inner wall surface of the upper header tank18bin the right space27. The nozzle support plate33and the nozzle portion14aare connected and fixed via the nozzle inlet pipe32. The point B3ofFIG. 4schematically shows a brazing position between the nozzle support plate33and the nozzle inlet pipe32.

The nozzle support plate33is located in the right space27to partition the right space27into two space parts in the tank longitudinal direction. A communication hole33athrough which the two space parts of the right space27communicates with each other is provided in the nozzle support plate33to penetrate through the nozzle support plate33.

The refrigerant flow in the entire evaporator unit20will be described with reference toFIGS. 2 and 3. First, refrigerant flows into the nozzle inlet pipe32from the refrigerant inlet30of the connection block29as shown in the arrow r1, and the refrigerant flowing into the nozzle inlet pipe32is branched into first and second streams. The refrigerant of the branched first stream flows straightly in the nozzle inlet pipe32and flows into the nozzle portion14aof the ejector14. In contrast, the refrigerant of the branched second stream flows into the right space27of the upper header tank18bvia the holes32aof the nozzle inlet pipe32.

The refrigerant flowing into the nozzle portion14aof the ejector14is jetted from the jet port of the nozzle portion14ato passes through the mixing portion14cand the diffuser14d, and flows into the left space26of the upper header tank15bof the first evaporator15. The refrigerant is decompressed while passing through the nozzle portion14aof the ejector14, and refrigerant in the left space28is drawn from the suction port14bby the jet flow of refrigerant jetted from the jet port of the nozzle portion14a. Therefore, the refrigerant jetted from the nozzle portion14aand the refrigerant drawn from the suction port14bare mixed in the mixing portion14c, and the mixed refrigerant is pressurized in the diffuser14d.

The refrigerant flowing out of the diffuser14dof the ejector14into the left space26of the upper header tank15bof the first evaporator15is distributed into the plural tubes21on the left side portion of the heat exchange core15a, and flows downwardly in the tubes21as in the arrow r2to be collected into the lower header tank15cof the first evaporator15. Because no partition plate is provided in the lower header tank15c, the refrigerant flows in the lower header tank15cas in the arrow r3from the left side to the right side inFIG. 2.

The refrigerant flowing into the right side portion within the lower header tank15cflows upwardly through the tubes21positioned at the right side portion of the heat exchange core15aas in the arrow r4inFIG. 2to flow into the right space25of the upper header tank15b. Furthermore, the refrigerant collected into the right space of the upper header tank15bof the first evaporator15flows out of the evaporator unit20via the refrigerant outlet31of the connection block29as in the arrow r5.

On the other hand, the refrigerant of the branched second stream flowing into the right space27of the upper header tank18bvia the holes32aof the nozzle inlet pipe32is distributed into the tubes21of the right side portion of the heat exchange core18aof the second evaporator18, and flows downwardly through the tubes21as in the arrow r6to collect the lower header tank18con the right side. Because no partition member is located in the lower header tank18c, the refrigerant flows in the lower header tank18cfrom the right side to the left side inFIG. 2as in the arrow r7.

The refrigerant on the left side of the lower header tank18cflows upwardly through the tubes21of the left side portion of the heat exchange core18aas in the arrow r8inFIG. 2, and is collected to the left space28of the upper header tank18b. The refrigerant in the left space28of the upper header tank18bis drawn into the mixing portion14cfrom the suction port14bof the ejector14by the jet flow of the refrigerant jetted from the nozzle portion14a, as described above.

Because the evaporator unit20has therein the refrigerant passage structure, the single refrigerant inlet30is provided in the connection block29to be used for the refrigerant passage structure of the evaporator unit20, and the single refrigerant outlet31is provided in the connection block29to be used for the refrigerant passage structure of the evaporator unit20.

Now, an operation of the refrigerant cycle device according to the first embodiment will be described. When the compressor11is driven by a vehicle engine, the high-temperature and high-pressure refrigerant compressed by and discharged from the compressor11flows into the radiator12where the high-temperature refrigerant is cooled and condensed by the outside air. The high-pressure refrigerant flowing out of the radiator12flows into the liquid receiver12awithin which the refrigerant is separated into liquid and vapor phases. The liquid refrigerant is derived from the liquid receiver12aand passes through the expansion valve13.

The expansion valve13adjusts the degree of opening of the valve to adjust a refrigerant flow amount, such that the superheat degree of the refrigerant on the refrigerant outlet side of the first evaporator15becomes a predetermined value, while the high-pressure refrigerant is decompressed. Here, the refrigerant on the refrigerant outlet side of the first evaporator15corresponds to the refrigerant to be drawn to the compressor11. The refrigerant having passed through the expansion valve13flows into the refrigerant inlet30provided in the connection block29of the evaporator unit20. The refrigerant after passing through the expansion valve13has a middle pressure.

The refrigerant flowing into the evaporator unit20from the refrigerant inlet30is branched at the branch portion Z to be divided into the refrigerant stream (first stream) directed to the nozzle portion14aof the ejector14, and the refrigerant stream (second stream) directed to the throttle17.

The refrigerant flowing into the ejector14is decompressed and expanded by the nozzle portion14a. Thus, the pressure energy of the refrigerant is converted into the speed energy at the nozzle portion14a, and the refrigerant is ejected from the jet port of the nozzle portion14aat high speed. At this time, the pressure drop of the refrigerant around the jet port of the nozzle portion14acauses to draw from the refrigerant suction port14b, the refrigerant (vapor-phase refrigerant) having passed through the heat exchange core18aof the second evaporator18.

The refrigerant ejected from the nozzle portion14aand the refrigerant drawn from the refrigerant suction port14bare combined in the mixing portion14con the downstream side of the nozzle portion14ato flow into the diffuser14d. In the diffuser14d, the speed (expansion) energy of the refrigerant is converted into the pressure energy by enlarging the passage sectional area, resulting in increased pressure of the refrigerant.

The refrigerant flowing out of the diffuser14dof the ejector14flows through the refrigerant flow paths indicated by the arrows r2to r5inFIG. 2. During this time, in the heat exchange core15aof the first evaporator15, the low-temperature and low-pressure refrigerant absorbs heat from the blown air in the direction of the arrow “A” so as to be evaporated. The vapor-phase refrigerant evaporated is drawn from the single refrigerant outlet26into the compressor11, and is compressed again in the compressor11.

The refrigerant flowing into the throttle17is decompressed to become a low-pressure refrigerant (liquid-vapor two-phase refrigerant). The low-pressure refrigerant flows through the refrigerant flow passages in the second evaporator18as indicated by the arrows r6to r8ofFIG. 2. During this time, in the heat exchange core18aof the second evaporator18, the low-temperature and low-pressure refrigerant absorbs heat from the blown air having passed through the first evaporator15to be evaporated. The vapor-phase refrigerant evaporated in the heat exchange core18aof the second evaporator18is drawn from the refrigerant suction port14binto the ejector14.

According to the first embodiment, because the nozzle portion14aof the ejector14can be brazed integrally with the first and second evaporators15,18in the evaporator unit20, the assemble work of the evaporator unit20can be made simple as compared with a case where the nozzle portion14ais assembled to the integrated structure of the first and second evaporators15,18after being brazed. Therefore, the productivity of the evaporator unit20can be improved while the manufacturing cost of the evaporator unit20can be reduced.

Furthermore, in a case where the mixing portion14cand the diffuser14dare fixed to the upper header tank18bby brazing, the entire of the ejector14can be integrally brazed to the first and second evaporators15,18. In this case, an assembling step for assembling the ejector14to the first and second evaporators15,18after brazing can be omitted. In this case, the productivity of the evaporator unit20can be further improved while the manufacturing cost of the evaporator unit20can be further reduced.

In the first embodiment, the nozzle portion14acan be brazed partially at the plural positions B1, B2separated from each other, a deformation of a very small passage within the nozzle portion14a, due to thermal contraction after the brazing, can be reduced, as compared with a case where all the outer surface of the nozzle portion14ais brazed.

Furthermore, the brazing positions B1and B2of the nozzle portion14aare arranged at positions except for the inlet and outlet of the nozzle portion14a. Therefore, it can prevent a brazing metal melted in the brazing from flowing into the very small passage in the nozzle portion14a, thereby preventing the very small passage in the nozzle portion14afrom being closed.

In the present embodiment, by simply forming the holes32ain the nozzle inlet pipe32, the branch passage16and the throttle mechanism17can be constructed in the evaporator unit20, thereby reducing the product cost.

Furthermore, because the plural holes32aare formed in the nozzle inlet pipe32at plural positions, it can prevent a bias flow of the refrigerant within the right space27of the upper header tank18bof the second evaporator18, so that the refrigerant can flow in uniform in the entire area of the right space27of the upper header tank18bof the second evaporator18.

According to the example ofFIG. 3of the first embodiment, because it is possible to adjust the insert dimension L of the nozzle portion14ainserted into the nozzle inlet pipe32, the compatibility of the ejector14relative to the first and second evaporators15,18having different dimensions in the tank longitudinal direction can be improved.

FIG. 5is a schematic sectional view showing a tank portion of an evaporator unit according to a modification of the first embodiment of the present invention. In the modification example ofFIG. 5, the dimension of both the first and second evaporators15,18in the tank longitudinal direction (i.e., the left-right direction inFIG. 5) is made larger than that ofFIG. 3. In the example ofFIG. 5, by setting the insertion length L of the nozzle portion14ainto the nozzle inlet pipe32to be smaller as compared with the example ofFIG. 3, the ejector14used in the example ofFIG. 3can be used for the first and second evaporators15,18.

As described above, by only changing the insertion length L between the nozzle portion14aand the nozzle inlet pipe32, the compatibility of the ejector14relative to various types of the first and second evaporators15,18with different lengths in the tank longitudinal direction (evaporator width direction) can be improved, thereby reducing the product cost.

The length of the nozzle inlet pipe32itself may be changed instead of the change of the insertion length L of the nozzle portion14ainto the nozzle inlet pipe32. Even in this case, the compatibility of the ejector14relative to the different widths of the first and second evaporators15,18can be obtained.

According to the first embodiment of the present invention, because the nozzle portion14ais supported by the partition plate24and the nozzle support plate33, the support strength of the nozzle portion14acan be improved, thereby reducing radiation noise from the first and second evaporators15,18.

Thus, a variation in the nozzle portion14acaused while the refrigerant passes in the nozzle portion14acan be reduced, thereby reducing a variation transmitted from the nozzle portion14ato the first and second evaporators15,18. Therefore, it can further reduce the radiation noise from the first and second evaporators15,18.

In addition, in the first embodiment of the present invention, the following advantages and effects can be obtained.

(1) Because the refrigerant downstream of the diffuser14dof the ejector14is supplied to the first evaporator15while the refrigerant branched at the branch portion Z is supplied to the second evaporator18via the throttle17, cooling capacity can be obtained in both the first and second evaporators15and18at the same time. Therefore, the air cooled by both the first and second evaporators15,18can be blown into a space to be cooled, thereby sufficiently cooling the space to be cooled.

The refrigerant evaporation pressure of the first evaporator15corresponds to the refrigerant pressure pressurized in the diffuser14d. On the other hand, because the refrigerant outlet side of the second evaporator18is connected to the refrigerant suction port14bof the ejector14, the lowest pressure immediately after the decompression of the nozzle portion14acan be applied to the second evaporator18.

Accordingly, the refrigerant evaporation pressure (refrigerant evaporation temperature) of the second evaporator18can be made lower than the refrigerant evaporation pressure (refrigerant evaporation temperature) of the first evaporator15. Furthermore, the first evaporator15having a relatively high refrigerant evaporation temperature is arranged upstream of the second evaporator18having a relatively low refrigerant evaporation temperature, in the flow direction A of air. Therefore, both a temperature difference between the refrigerant evaporation temperature and the temperature of the blown air in the first evaporator15, and a temperature difference between the refrigerant evaporation temperature and the temperature of the blown air in the second evaporator18can be sufficiently obtained.

Therefore, cooling performance can be improved in both of the first evaporator15and the second evaporator18, thereby improving cooling performance by using the combination of both the first and second evaporators15,18. Furthermore, because the refrigerant pressure is increased in the diffuser14dof the ejector14, the refrigerant suction pressure of the compressor11can be increased, thereby reducing the drive power of the compressor11.

(2) The refrigerant downstream area (e.g., right upper area ofFIG. 2) in the heat exchange core15aof the first evaporator15and the refrigerant downstream area (e.g., left upper area ofFIG. 2) in the heat exchange core18aof the second evaporator18are arranged to be shifted from each other when being viewed from the flow direction A of air. That is, the refrigerant superheat area in the heat exchange core15aof the first evaporator15and the refrigerant superheat area in the heat exchange core18aof the second evaporator18are arranged to be shifted from each other when being viewed from the flow direction A of air. Therefore, the air having passed through the refrigerant superheat area of the first evaporator15can be sufficiently cooled by the second evaporator18.

On the other hand, the air to pass through the refrigerant superheat area of the second evaporator18can be sufficiently cooled in the first evaporator15. As a result, it can prevent the temperature distribution of air blown from the second evaporator18from being greatly different from each other.

(3) Furthermore, because the ejector14is located inside the upper header tank18bof the second evaporator18, the mounting performance of the evaporator unit20can be improved, and the pressure loss caused in the refrigerant cycle device can be reduced. Furthermore, because the refrigerant inlet30and the refrigerant outlet31are arranged adjacent to each other in the evaporator unit20, the evaporator unit20can be easily connected to other components of the refrigerant cycle device, thereby improving the mounting performance of the refrigerant cycle device.

In the above-described first embodiment, the inlet side portion of the nozzle portion14ais inserted into the nozzle inlet pipe32. However, a downstream end portion of the nozzle inlet pipe32may be inserted into the inlet side portion of the nozzle portion14a.

Second Embodiment

In the above-described first embodiment, the nozzle portion14aand the mixing portion14care located separately from each other. However, in the second embodiment, as shown inFIG. 6, the nozzle portion14aand the mixing portion14care connected in the ejector14.

A pipe portion34is formed at a tip end portion (downstream end portion) of the nozzle portion14a. The pipe portion34is inserted into an inlet portion of the mixing portion14c, and an outer peripheral surface of the pipe portion34is brazed onto an inner peripheral surface of the mixing portion14cin the inserted portion, thereby air-tightly fixing the pipe portion34to the mixing portion14cof the ejector14. In this case, assemble accuracy such as a coaxial accuracy between the mixing portion14cand the nozzle portion14acan be improved in the ejector14.

A hole is provided in a pipe wall of the pipe portion34at a position outside of the mixing portion14cso as to define and construct the refrigerant suction port14b.

In the above-described first embodiment, the inlet side portion of the nozzle portion14ais inserted into the nozzle inlet pipe32. However, in the second embodiment, as shown inFIG. 6, an end portion of the nozzle inlet pipe32is inserted into the inlet side portion of the nozzle portion14aso as to have an insertion length L.

Thus, in the second embodiment of the present invention, the nozzle support plate33and the nozzle portion14acan be directly fixed by brazing without interposing the nozzle inlet pipe32therebetween. The end portion of the nozzle inlet pipe32is air-tightly connected to the inlet portion of the nozzle portion14aby brazing.

In the second embodiment, the other parts of the evaporator unit20may be similar to those of the above-described first embodiment.

Third Embodiment

A third embodiment of the present invention will be described with reference toFIGS. 7 and 8. In the above-described first embodiment, the ejector14is located inside the upper header tank18bof the second evaporator18. However, in the third embodiment, a separate tank40is located separately from the upper header tanks15b,18b, to accommodate therein the ejector14. That is, the separate tank40is located outside the upper header tanks15band18bat a valley portion between the upper header tanks15band18bto contact both the upper header tanks15band18b. The separate tank40can be used exclusively for the ejector14.

The separate tank40has a cylindrical shape extending in the tank longitudinal direction of the upper header tanks15b,18b. The separate tank40is located at the valley portion between the upper header tanks15band18b, and is integrally brazed to the outer surfaces of the upper header tanks15b,18b. In the third embodiment, the inner diameter of the separate tank40is set in constant.

A communication hole41, through which the left space28of the upper header tank18bof the second evaporator18communicates with the inside of the separate tank40, is provided at a position corresponding to a middle portion in the longitudinal direction of the separate tank40. In the example ofFIG. 7, one communication hole41is provided such that the left space28of the upper header tank18bof the second evaporator18communicates with the inside of the separate tank40through the communication hole41. However, plural communication holes41may be provided at different positions. For example, the plural communication holes41may be provided at different positions in the longitudinal direction of the separate tank40, or at different positions in the circumferential direction of the cylindrical shape of the separate tank40.

An end surface (not shown) of one end side (e.g., the right end side inFIG. 8) of the separate tank40in the longitudinal direction is fixed to the connection block29by brazing. The other end side (e.g., the left end side inFIG. 8more than the communication hole41) of the separate tank40is made to communicate with the left space26of the upper header tank15bof the first evaporator15via a communication hole.

The nozzle portion14aof the ejector14is located in the separate tank40such that the jet port of the nozzle portion14ais open toward the other end side (e.g., the left end side inFIG. 8) of the separate tank40. Furthermore, a tip portion of the nozzle portion14ais formed into a taper shape at a refrigerant outlet side. The taper-shaped tip portion of the nozzle portion14ais positioned to face the communication hole41, so that the arrangement position of the nozzle portion14aof the ejector14can be determined. In the example ofFIG. 8, the outer diameter of the nozzle portion14aexcept for the taper-shaped tip portion has generally a constant outer diameter, and all the nozzle portion14ais located in the separate tank40.

The mixing portion14cand the diffuser14dof the ejector14are provided downstream of the nozzle portion14awithin the separate tank40although it is omitted inFIG. 8. For example, similarly to the first embodiment, the inlet side opening portion of the mixing portion14cmay be configured to define the suction port14bof the ejector14. Furthermore, a suction refrigerant passage42, through which the refrigerant to be drawn into the refrigerant suction port14bflows, is provided at a radial outside of the taper-shaped tip portion of the nozzle portion14a.

The nozzle portion14ais temporally fixed into the separate tank40by using a fastening member, or by fitting the nozzle portion14ainto the separate tank40. When the nozzle portion14ais temporally fixed to the separate tank40by fitting the nozzle portion14ainto the separate tank40, the outer peripheral surface of the nozzle portion14ais used as a temporally fixing portion. When the nozzle portion14ais temporally fixed to the separate tank40by using a fastening member on the nozzle portion14a, the fastening portion is used as the temporally fixing portion.

After the nozzle portion14ais temporally fixed into the separate tank40at the fastening portion, the nozzle portion14ais integrally brazed to the separate tank40together with the evaporator unit20. For example, the outer peripheral surface of the nozzle portion14aexcept for the taper-shaped tip portion is brazed to the separate tank40. In this case, the outer peripheral surface of the nozzle portion14aexcept for the position facing the suction refrigerant passage42can be brazed to the separate tank40.

As an example, the nozzle portion14ais formed by a clad material such that a brazing material is applied to the outer peripheral surface of the nozzle portion14a. In this case, the nozzle portion14acan be easily brazed integrally with the separate tank40. The separate tank40may be formed by a clad material such that an inner wall surface of the separate tank40is covered by a brazing material, instead of the nozzle portion14a. Alternatively, both the nozzle portion14aand the separate tank40may be formed by a clad material such that the outer peripheral surface of the nozzle portion14aand the inner wall surface of the separate tank40are covered by a brazing material.

The mixing portion14cand the diffuser14dof the ejector14may be fixed to the separate tank40by brazing similarly to that of the nozzle portion14a, or may be fixed by using a suitable fastening member.

In the third embodiment, because the ejector14is not located inside the upper header tank18bof the second evaporator18, the nozzle inlet pipe32described in the first embodiment may be omitted.

In the third embodiment, the connection block29is configured to have a branch portion with a branch function for branching the refrigerant flowing from the refrigerant inlet30into the refrigerant stream flowing toward the right space27of the upper header tank18band the refrigerant stream flowing into the inlet side end portion of the nozzle portion14a. The connection block29with the branch function is not shown.

In the above-described first embodiment, the throttle17is configured by using the holes32aof the nozzle inlet pipe32. However, in the third embodiment, the throttle17is configured by using an orifice hole (not shown) that is provided in a communication portion between the connection block29and the right space27of the upper tank18b.

Next, a refrigerant flow passage in the evaporator unit20according to the third embodiment of the present invention will be described with reference toFIGS. 2,7and8. The refrigerant flowing into the right space27of the upper header tank18bfrom the refrigerant inlet30of the connection block29is branched into a refrigerant stream flowing into one side (e.g., right side inFIG. 8) of the longitudinal direction of the separate tank40, and a refrigerant stream distributed into the tubes21of the right side portion of the heat exchange core18aof the second evaporator18.

The refrigerant flowing into the one side (e.g., right side inFIG. 8) of the longitudinal direction of the separate tank40flows into the nozzle portion14aof the ejector14to be jetted from the nozzle portion14a, and passes through the mixing portion14cand the diffuser14din the separate tank40. The refrigerant is decompressed while passing through the nozzle portion14aof the ejector14, is mixed with the refrigerant drawn from the refrigerant suction port14bin the mixing portion14c, and is pressurized in the diffuser14dof the ejector14.

Low-pressure refrigerant after the decompression in the ejector14flows out of the other end side (e.g., left side inFIG. 8) of the longitudinal direction of the separate tank40, and flows into the left space26of the upper header tank15bof the first evaporator15via the communication hole (not shown). The refrigerant flowing into the left space26of the upper header tank15bflows in the refrigerant passages as in the arrows r2to r5ofFIG. 2, and flows out of the refrigerant outlet31of the connection block29.

In contrast, the refrigerant distributed into the plural tubes21of the right side portion of the heat exchange core18aof the second evaporator18flows in the refrigerant passages as in the arrows r6to r8ofFIG. 2, and is joined to the left space28of the upper header tank18b.

Then, as shown inFIG. 7, the refrigerant collected to the left space28of the upper header tank18bflows into the separate tank40via the communication hole41, and is drawn into the mixing portion14cof the ejector14from the suction port14bof the ejector14via the suction refrigerant passage42.

In the third embodiment, because the nozzle portion14aof the ejector14is brazed integrally with the separate tank40, the forming work for forming the evaporator unit can be made simple as compared with a case where the nozzle portion14ais assembled to the separate tank40after the brazing of the separate tank40.

Furthermore, because the nozzle portion14ais brazed on its outer peripheral surface to the separate tank40, it can prevent a melted brazing material from flowing into the very small passage of the nozzle portion14a, thereby preventing the very small passage of the nozzle portion14afrom being closed.

Furthermore, because the brazing position of the nozzle portion14ais set at the position except for the suction refrigerant passage42, it can prevent the melted brazing material from flowing into the suction refrigerant passage42. Therefore, the suction refrigerant passage42is not narrowed or closed by the melted brazing material.

In the third embodiment, the other parts of the evaporator unit20including the separate tank40may be similar to those of the above-described first embodiment.

Fourth Embodiment

A fourth embodiment of the present invention will be now described with reference toFIG. 9. The fourth embodiment is a modification of the above-described third embodiment.

In the above-described third embodiment of the present invention, the inner diameter of the cylindrical separate tank40is made constant. However, in the fourth embodiment, as shown inFIG. 9, the inner diameter of the separate tank40at a brazing portion, to which the nozzle portion14ais brazed, is made smaller than the inner diameter of the separate tank40at the remaining portion other than the brazing portion.

According to the fourth embodiment, the passage sectional area of the suction refrigerant passage42can be made larger than that of the third embodiment, and thereby the refrigerant can be smoothly drawn into the mixing portion14cfrom the refrigerant suction port14bof the ejector14via the suction refrigerant passage42.

In the fourth embodiment, the other pasts of the evaporator unit may be similar to those of the above-described third embodiment.

Fifth Embodiment

A fifth embodiment of the present invention will be now described with reference toFIG. 10. The fifth embodiment is another modification of the above-described third embodiment.

In the above-described fourth embodiment, the inner diameter of the separate tank40is made smaller in a relative wide range so that the outer peripheral surface of the nozzle portion14acan be brazed to the separate tank40in the relatively wide range. However, in the fifth embodiment, the inner diameter of the separate tank40is reduced partially in a small area, so that the nozzle portion14acan be brazed in a small part relative to the separate tank40.

According to the fifth embodiment of the present invention, it can reduce a deformation of the very small passage (fine passage) within the nozzle portion14a, due to a thermal contraction, as compared with the fourth embodiment. Accordingly, the arrangement position of the communication hole41can be easily set as compared with the above-described fourth embodiment.

In the example ofFIG. 10, the inner diameter of the separate tank40is reduced at one position in the longitudinal direction of the separate tank40. However, the inner diameter of the separate tank40may be reduced partially at plural positions such that the nozzle portion14acan be brazed to the separate tank40at the plural positions.

In the fifth embodiment, the other parts of the integrated unit may be similar to those of the above-described third embodiment.

Sixth Embodiment

A sixth embodiment of the present invention will be now described with reference toFIGS. 11A and 11B. The sixth embodiment is another modification of the above-described third embodiment.

In the above-described fifth embodiment, the inner diameter of the separate tank40is partially reduced. However, in the sixth embodiment, as shown inFIGS. 11A and 11B, the inner diameter of the separate tank40is made constant, and an interposition member43is located at a portion between the outer peripheral surface of the nozzle portion14aand the inner wall surface of the separate tank40.

The interposition member43is made of metal such as aluminum having a sufficient brazing property, and is brazed integrally with the nozzle portion14a. In the present embodiment, the interposition member43is a circular plate having a hole at its center area. The nozzle portion14ais fitted into the hole of the interposition member43and is brazed integrally with the interposition member43.

The interposition member43can be fixed into the separate tank40by fitting or using a fastening member, without being limited to a brazing. When the interposition member43is fixed by fastening, a protrusion portion for the fastening may be provided on the interposition member43. Thus, in the sixth embodiment, the effects and advantages described in the fifth embodiment can be obtained.

In the example ofFIGS. 11A and 11B, the interposition member43may be arranged at a single position. However, a plurality of the interposition members43may be located at plural positions in the longitudinal direction of the nozzle portion14a.

In the sixth embodiment, the other parts of the evaporator unit may be similar to those of the above-described third embodiment.

Seventh Embodiment

A seventh embodiment of the present invention will be now described with reference toFIG. 12. The seventh embodiment is another modification of the above-described third embodiment.

In the above-described fifth embodiment, the inner diameter of the separate tank40is partially reduced while the outer diameter of the nozzle portion14aexcept for the taper-shaped tip portion is made substantially constant. However, in the seventh embodiment, the outer diameter of the nozzle portion14aexcept for the taper-shaped tip portion is partially increased while the inner diameter of the separate tank40is made constant. Accordingly, in the seventh embodiment, the advantages and effects described in the fifth embodiment can be obtained.

In the example ofFIG. 12, the outer diameter of the nozzle portion14ais enlarged radially at a single position except for the taper-shaped tip portion, relative to the separate tank40, in the longitudinal direction of the nozzle portion14a. However, the outer diameter of the nozzle portion14acan be enlarged radially at plural positions except for the taper-shaped tip portion, relative to the separate tank40, in the longitudinal direction of the nozzle portion14a.

In the seventh embodiment, the other parts of the evaporator unit may be similar to those of the above-described third embodiment.

Eighth Embodiment

An eighth embodiment of the present invention will be now described with reference toFIG. 13. The eighth embodiment is another modification of the above-described third embodiment.

In the above-described third embodiment, all the nozzle portion14ais located within the separate tank40. However, in the eighth embodiment, as shown inFIG. 13, the inlet-side end portion (e.g., the right end portion inFIG. 13) of the nozzle portion14ais located to slightly protrude outside from the separate tank40. The protruding end portion of the nozzle portion14ais configured to have a flange portion44protruding radially outwardly from the inner wall surface of the separate tank40.

Thus, in the present embodiment, the outer peripheral surface of the nozzle portion14aexcept for the taper-shaped tip portion is brazed to the inner wall surface of the separate tank40, and the flange portion44of the nozzle portion14acan contact the end surface of the separate tank40to be brazed to the end surface of the separate tank40.

According to the eighth embodiment of the present invention, the flange portion44provided in the end portion of the nozzle portion14ais made to contact the end surface of the separate tank40, and thereby the longitudinal position of the nozzle portion14arelative to the separate tank40can be regulated. Thus, the arrangement position of the nozzle portion14acan be easily and accurately set in the separate tank40.

In the eighth embodiment, the other parts of the evaporator unit may be similar to those of the above-described third embodiment.

Ninth Embodiment

A ninth embodiment of the present invention will be described with reference toFIG. 14. The ninth embodiment is another modification of the above-described third embodiment. In the above-described eighth embodiment, both the outer peripheral surface and the flange portion44of the nozzle portion14aare brazed to the separate tank40. However, in the ninth embodiment, as shown inFIG. 14, a predetermined clearance is formed between the outer peripheral surface of the nozzle portion14aand the inner wall surface of the separate tank40, and only the flange portion44of the nozzle portion14ais brazed to the separate tank40.

According to the ninth embodiment, because the clearance is formed between the outer peripheral surface of the nozzle portion14aand the inner wall surface of the separate tank40, the communication hole41can be easily provided in the separate tank40.

However, in the ninth embodiment, the outer peripheral surface of the nozzle portion14amay partially protrude radially outside to be partially brazed to the inner wall surface of the separate tank40.

In the ninth embodiment, the other parts of the evaporator unit may be similar to those of the above-described third embodiment.

Tenth Embodiment

A tenth embodiment of the present invention will be described with reference toFIG. 15. The tenth embodiment is another modification of the above-described third embodiment. In the above-described ninth embodiment, only the flange portion44of the nozzle portion14ais brazed to the separate tank40. However, in the tenth embodiment, as shown inFIG. 15, the outer diameter of a part of the nozzle portion14aadjacent to the flange portion44is made larger so that the flange portion44and the portion adjacent to the flange portion44of the nozzle14aare brazed to the separate tank40.

In the tenth embodiment, the brazing area between the nozzle portion14aand the separate tank40can be made larger, thereby accurately brazing the nozzle portion14ato the separate tank40.

In the tenth embodiment, the other parts of the evaporator unit may be similar to those of the above-described third embodiment.

Eleventh Embodiment

An eleventh embodiment of the present invention will be described with reference toFIG. 16. The eleventh embodiment is another modification of the above-described third embodiment. In the above-described third embodiment, at least one of the nozzle portion14aand the separate tank40are formed by a clad material so that the nozzle portion14aand the separate tank40are integrally brazed. However, in the eleventh embodiment, both the nozzle portion14aand the separate tank40are not formed by a clad material with a brazing material, but both the nozzle portion14aand the separate tank40are integrally brazed by using a separate brazing material45.

For example, the inlet-side end portion of the nozzle portion14aslightly protrudes from an end surface of the separate tank40, and a brazing material45is arranged in a corner wall portion between the protruding end portion of the nozzle portion14aand the end surface of the separate tank40, as shown inFIG. 16. In the example ofFIG. 16, the brazing material45is formed into a ring shape to be arranged along the entire periphery of the corner portion between the protruding end portion of the nozzle portion14aand the end surface of the separate tank40. However, the brazing material45may be arranged only a part of the corner portion in the circumferential direction.

In the eleventh embodiment, the nozzle portion14aand the separate tank40are brazed at the corner wall portion by using the brazing material45located at the corner wall portion. In addition, the brazing material45melted in the brazing flows into a clearance between the outer peripheral surface of the nozzle portion14aand the inner wall surface of the separate tank40by capillary phenomenon so as to braze the outer peripheral surface of the nozzle portion14aand the inner wall surface of the separate tank40to each other. Accordingly, in the eleventh embodiment, the effects described in the third embodiment can be also obtained.

Twelfth Embodiment

A twelfth embodiment of the present invention will be described with reference toFIG. 17. The twelfth embodiment is another modification of the above-described third embodiment.

In the above-described eleventh embodiment of the present invention, the outer diameter of the portion of the nozzle portion14aexcept for the taper-shaped tip portion on the refrigerant outlet side is made constant. However, in the twelfth embodiment, as shown inFIG. 17, the outer diameter of an upstream portion of the nozzle portion14aupstream from the communication hole41in a refrigerant flow is made larger so that the upstream portion of the nozzle portion14ais brazed to the inner wall surface of the separate tank40.

According to the twelfth embodiment, because the clearance is formed between the outer peripheral surface of the nozzle portion14aand the inner wall surface of the separate tank40on a relatively upstream side in the refrigerant flow, the communication hole41can be easily provided in the separate tank40.

In the twelfth embodiment, the other parts of the evaporator unit may be similar to those of the above-described third embodiment.

Thirteenth Embodiment

A thirteenth embodiment of the present invention will be described with reference toFIGS. 18 and 19. The thirteenth embodiment is another modification of the above-described third embodiment.

In the above-described eleventh embodiment, the inlet-side end portion of the nozzle portion14ais arranged to slightly protrude from the end surface of the separate tank40, and the brazing material45is located in the corner wall portion between the inlet-side end portion of the nozzle portion14aand the end surface of the separate tank40. However, in the thirteenth embodiment, as shown inFIG. 18, all the nozzle portion14ais arranged within the separate tank40, and a recess portion46is provided on the outer peripheral surface of the nozzle portion14a. Furthermore, a brazing material45is arranged in the recess portion46between the outer peripheral surface of the nozzle portion14aand the inner wall surface of the separate tank40.

In the example ofFIG. 18, the brazing material45and the recess portion46are formed into ring shapes. However, the brazing material45and the recess portion46may be formed into other shapes without being limited to the ring shapes. For example, the brazing material45and the recess portion46may be formed partially in the circular direction. In the example ofFIG. 18, the recess portion46may be formed by plastic processing, or may be formed by cutting.

In the thirteenth embodiment of the present invention, the nozzle portion14aand the separate tank40are brazed at the recess portion46by using the brazing material45. In addition, the brazing material45melted in the brazing flows into a clearance between the outer peripheral surface of the nozzle portion14aand the inner wall surface of the separate tank40by capillary phenomenon so as to braze the outer peripheral surface of the nozzle portion14aand the inner wall surface of the separate tank40to each other. Accordingly, in the eleventh embodiment, the effects described in the third embodiment can be also obtained.

FIG. 19is a modification of the above-described thirteenth embodiment. In the example ofFIG. 19, the brazing material45and the recess portion46can be located at plural positions in the longitudinal direction of the nozzle portion14a. In the examples ofFIGS. 18 and 19, the recess portion46is provided on the outer peripheral surface of the nozzle portion14aso that the brazing material45is arranged in the recess portion46between the nozzle portion14aand the separate tank40. However, the recess portion46may be provided on the inner wall surface of the separate tank40so that the brazing material45is arranged in the recess portion46between the nozzle portion14aand the separate tank40.

In the thirteenth embodiment, the other parts of the evaporator unit may be similar to those of the above-described third embodiment.

Fourteenth Embodiment

A fourteenth embodiment of the present invention will be described with reference toFIG. 20. The fourteenth embodiment is another modification of the above-described third embodiment.

In the above-described thirteenth embodiment, the portion except for the tip portion of the nozzle portion14aon its refrigerant outlet side is formed to have a constant outer diameter. However, in the fourteenth embodiment, as shown inFIG. 20, the outer diameter of an upstream portion of the nozzle portion14aupstream from the communication hole41in the refrigerant flow is partially enlarged to be brazed to the inner wall surface of the separate tank40. In this case, the arrangement position of the communication hole41can be easily set in the longitudinal direction of the separate tank40. Even in this case, the brazing material45and the recess portion46can be provided between the outer peripheral surface of the nozzle portion14aand the inner wall surface of the separate tank40, as shown inFIG. 20. Furthermore, as shown inFIG. 20, the outer diameter of the downstream end portion of the nozzle portion14amay be reduced gradually or in irregular, without being limited to the taper shape.

Other Embodiments

It should be understood that the present invention is not limited to the above-mentioned embodiments, and various modifications can be made to the present embodiments as follows.

In the above-described first and second embodiments, the throttle17is configured by using the hole32aof the nozzle inlet pipe32. However, the throttle17may be configured by using a capillary tube. In this case, the hole32amay be omitted in the nozzle inlet pipe32, and the branch portion Z and the branch passage16are provided in the connection block29. Furthermore, the capillary tube may be arranged in the upper header tank18bof the second evaporator18to be parallel with the nozzle inlet pipe32, such that one end portion of the capillary tube communicates with the branch passage16, and the other end portion of the capillary tube is directly open to the right space27of the upper header tank18b.

Accordingly, the refrigerant branched at the branch portion Z in the connection block29can be decompressed in the capillary tube used as the throttle, and thereafter can flows into the right space27of the upper header tank18b.

In the above-described embodiments, the first evaporator15, the second evaporator18and the ejector14are integrally constructed as the evaporator unit20. However, the other components may be integrated in the evaporator unit20.

For example, the thermal expansion valve13and the temperature sensing portion13amay be also integrated in the evaporator unit20.

In the above-described embodiments, the first evaporator15and the second evaporator18are arranged adjacent to each other to be integrally constructed in the evaporator unit20. However, the structure of the evaporator unit20is not limited to the structure shown inFIG. 2, and may be suitably changed.

For example, the first evaporator15and the second evaporator18may be arranged to be spaced from each other by a predetermined distance, and a refrigerant pipe may be located such that the inner spaces of the upper header tanks15b,18bof the first and second evaporators15,18communicate with each other via the refrigerant pipe.

Although in the above-described embodiments, the vapor-compression subcritical refrigerant cycle has been described in which the refrigerant is a flon-based one, an HC-based one, or the like, whose high pressure does not exceed the critical pressure of the refrigerant, the present invention may be applied to a vapor-compression supercritical refrigerant cycle which employs the refrigerant, such as carbon dioxide (CO2), whose high pressure exceeds the critical pressure of the refrigerant.

In the supercritical refrigerant cycle, only the refrigerant discharged by the compressor11dissipates heat in the supercritical state at the radiator12, and hence is not condensed. Thus, the liquid receiver12adisposed on the high-pressure side cannot exhibit a liquid-vapor separation effect of the refrigerant, and a retention effect of the excessive liquid refrigerant. The supercritical cycle may have the structure including an accumulator at the outlet of the first evaporator15. In this case, the accumulator is used as a low-pressure gas-liquid separator.

In the above supercritical refrigerant cycle, the branch portion Z upstream of the nozzle portion14aof the ejector14may be omitted. In this case, a downstream side of the thermal expansion valve13is connected to the nozzle portion14aof the ejector14, and liquid refrigerant separated at the accumulator is made to flow into the heat exchange core18aof the second evaporator18.

Although in the above-mentioned embodiments, the ejector14is a fixed ejector having the nozzle portion14awith the certain path area, the ejector14for use may be a variable ejector having a variable nozzle portion whose path area is adjustable.

For example, the variable nozzle portion may be a mechanism which is designed to adjust the path area by controlling the position of a needle inserted into a passage of the variable nozzle portion using the electric actuator.

Although in the above-described first embodiment, the evaporator unit20is used as an interior heat exchanger, and the radiator12is used as the exterior heat exchanger. However, the evaporator unit20may be used as an exterior unit configured to absorb heat from outside air as a heat source, and the radiator12may be used as an interior heat exchanger for heating a fluid such as water or air, in a heat pump cycle.

In the above-described embodiments, the refrigerant cycle device having the evaporator unit20is used for a vehicle. However, the refrigerant cycle device having the evaporator unit20may be used for a fixed room without being limited to the vehicle.

Any two of the above-described embodiments may be suitably combined without being limited to the example shown in each embodiment.

In the above-described third to fourteenth embodiments, the ejector40is located inside the separate tank40. However, the ejector14according to any one of the third to fourteenth embodiments may be located inside the upper header tank18bof the second evaporator18. In this case, the upper header tank18bmay be configured to have the structure of the separate tank40in the integrated unit20.

In the above-described embodiments, the thermal expansion valve13is used in the refrigerant cycle device10. However, thermal expansion valve13may be omitted, and a mechanical expansion valve or an electrical expansion valve may be used instead of the thermal expansion valve13.

In the above-described first embodiment, the tanks15b,15c,18b, and18cof the first evaporator15and the second evaporator18are disposed on both the upper and lower sides of the first and second evaporators15,18, that is, the first evaporator15and the second evaporator18are disposed vertically. Alternatively, the first evaporator15and the second evaporator18may be disposed in a slanted manner with respect to the vertical direction. Furthermore, the first evaporator15and the second evaporator18may be located to cool different spaces without being limited to the common space.

Furthermore, in the above described embodiments, the ejector14may be located in the header tank15bof the first evaporator15connected to the refrigerant suction side of the ejector14or the header tank18bof the second evaporator18connected to the refrigerant outlet of the ejector14in the evaporator unit20. That is, the second evaporator18with the ejector14described above may be used as an evaporator in the present invention.

According to an aspect of the present invention, an evaporator unit20includes an ejector14and an evaporator (18). The ejector14has a nozzle portion14awhich decompresses refrigerant, and a refrigerant suction port14bfrom which refrigerant is drawn by a high-speed refrigerant flow jetted from the nozzle portion14a. The refrigerant jetted from the nozzle portion14aand the refrigerant drawn from the refrigerant suction port14bare mixed in the ejector14and discharged from an outlet of the ejector14. The evaporator (18) is connected to the ejector14to evaporate the refrigerant to be drawn into the refrigerant suction port14bor the refrigerant flowing out of the outlet of the ejector14. Furthermore, the evaporator18includes a plurality of tubes21in which the refrigerant flows, and a tank (18b,40) configured to distribute the refrigerant into the tubes21or to collect the refrigerant from the tubes21. The ejector14is located in the tank (18b,40), and the nozzle portion14ais brazed to the tank (18b,40) to be fixed into the tank (18b,40). Accordingly, the ejector14including the nozzle portion14acan be brazed integrally with the tank (18b,40), thereby improving the productivity of an evaporator unit while reducing the manufacturing cost of the evaporator unit.

The tank (18b,40) may be a header tank such as the upper header tank18bdirectly connected to the tubes21or may be a separate tank40separated from the header tank.