Evaporator

Abstract

To provide an evaporator that can improve the temperature distribution of the heat exchange section while suppressing oil stagnation. [Solution] The indoor evaporator 10 is applied to a vapor compression type refrigeration cycle system. The indoor evaporator 10 comprises a plurality of tubes 20 through which a refrigerant mixed with oil flows in the vertical direction, and a lower tank section 50 connected to the lower end of each tube 20, which collects the refrigerant flowing through some of the tubes 20 and distributes the refrigerant to the other tubes 20. The lower tank section 50 includes a cylindrical section 52 that forms a refrigerant flow passage 520, and a separator 60 that forms a throttling passage 61 smaller than the cross-sectional area of ​​the flow passage 520 in the cylindrical section 52. The throttling passage 61 is formed to be close to the cylindrical bottom wall 521 which is the bottom of the cylindrical section 52.

Description

Technical Field

[0001] The present disclosure relates to an evaporator applied to a vapor compression refrigeration cycle device.

Background Art

[0002] Conventionally, there is known an evaporator including a plurality of tubes through which a refrigerant flows, and a lower tank that collects the refrigerant passing through some of the tubes and distributes it to other tubes, and a separator provided with a throttle hole inside the lower tank (see, for example, Patent Document 1). This Patent Document 1 describes that by restricting the refrigerant flow by the throttle hole of the separator, the speed of the refrigerant flow is increased, and the refrigerant is blown to the back of the lower tank, thereby improving the temperature distribution in the heat exchange section including the plurality of tubes.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] <000o025>By the way, in a vapor compression refrigeration cycle device, oil (so-called refrigeration machine oil) for lubricating a compressor is mixed with the refrigerant, and a part of the oil circulates in the cycle together with the refrigerant. When a separator with a throttle hole is arranged in the lower tank of the evaporator as in Patent Document 1, there is a risk that the oil flowing into the tank cannot pass through the throttle hole and stays in the tank as it is. The retention of oil in the tank is not preferable because it causes a shortage of oil supply to the compressor.

[0005] An object of the present disclosure is to provide an evaporator capable of improving the temperature distribution in a heat exchange section while suppressing the retention of oil.

Means for Solving the Problems

[0006] The invention described in claim 1 is, An evaporator applied to a vapor compression type refrigeration cycle system, Multiple tubes (20) through which the oil-mixed refrigerant flows in an up-and-down direction, It comprises a lower tank section (50) connected to the lower end of multiple tubes, which collects the refrigerant flowing through some of the tubes and distributes the refrigerant to the other tubes, The lower tank section is, A cylindrical portion (52) that forms a refrigerant flow passage (520), It includes a separator (60) that forms a throttling channel (61) smaller than the cross-sectional area of ​​the flow passage in the cylindrical part, The throttling channel is formed to be close to the bottom wall (521) of the cylindrical section.

[0007] Thus, if a throttling passage is provided in the lower tank section, the refrigerant flow is restricted in the throttling passage, increasing the velocity of the refrigerant flow and making it easier for the refrigerant to reach the back of the lower tank section. This improves the temperature distribution in the heat exchange section of the evaporator. In addition, the evaporator of this disclosure is formed so that the throttling passage is close to the bottom wall of the cylindrical section that forms the bottom of the lower tank section. As a result, the movement of oil is less likely to be restricted by the separator provided in the lower tank section, and oil stagnation in the evaporator is suppressed.

[0008] The reference numerals in parentheses attached to each component indicate an example of the correspondence between that component and the specific components described in the embodiments described later. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of a refrigeration cycle system including an evaporator according to the first embodiment. [Figure 2] This is a schematic perspective view of the evaporator according to the first embodiment. [Figure 3] This is a schematic front view of the evaporator according to the first embodiment. [Figure 4] It is a schematic cross-sectional view of the lower tank portion of the evaporator according to the first embodiment. [Figure 5] It is an explanatory diagram for explaining the oil retention in the evaporator as a comparative example of the first embodiment. [Figure 6] It is an explanatory diagram for explaining the way the oil flows in the evaporator according to the first embodiment. [Figure 7] It is an explanatory diagram for explaining the performance, oil circulation rate, etc. of the refrigeration cycle device including the evaporator according to the first embodiment. [Figure 8] It is an explanatory diagram for explaining the operation of the refrigeration cycle device including the evaporator according to the first embodiment. [Figure 9] It is a schematic cross-sectional view of the lower tank portion as a modification of the first embodiment. [Figure 10] It is a schematic cross-sectional view showing a part of the evaporator according to the second embodiment. [Figure 11] It is a schematic cross-sectional view of the lower tank portion of the evaporator according to the second embodiment. [Figure 12] It is a schematic cross-sectional view of the lower tank portion as a modification of the second embodiment. [Figure 13] It is a schematic cross-sectional view showing a part of the evaporator according to the third embodiment. [Figure 14] It is a schematic cross-sectional view of the lower tank portion of the evaporator according to the third embodiment. [Figure 15] [[ID=3⑤]]It is a cross-sectional view taken along the line XV-XV of FIG. 14. [Figure 16] It is a schematic cross-sectional view of the lower tank portion as a modification of the third embodiment. [Figure 17] It is a schematic cross-sectional view of the lower tank portion of the evaporator according to the fourth embodiment.

Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, parts that are the same as or equivalent to those described in the preceding embodiments may be denoted by the same reference numerals, and the description thereof may be omitted. Further, in the embodiments, when only a part of the components is described, the components described in the preceding embodiments can be applied to the other parts of the components. The following embodiments can be partially combined with each other as long as there is no problem in the combination, even if not particularly specified.

[0011] (First Embodiment) This embodiment will be described with reference to FIGS. 1 to 8. In this embodiment, an example in which the "evaporator" of the present disclosure is applied to the indoor evaporator 10 of the vapor compression refrigeration cycle device 1 will be described. The refrigeration cycle device 1 is applied to, for example, a vehicle air conditioner mounted on an electric vehicle that obtains driving force for vehicle travel from an electric motor. The refrigeration cycle device 1 has a function as an air conditioner that adjusts the temperature of the blown air blown into the vehicle interior, which is the air-conditioning target space, and also has a function as a cooling device for a battery that supplies power to the electric motor for vehicle travel.

[0012] For the refrigerant of the refrigeration cycle device 1, for example, an HFC-based refrigerant is adopted. The refrigeration cycle device 1 of this embodiment constitutes a subcritical refrigeration cycle in which the pressure of the high-pressure refrigerant discharged from the compressor 2 does not exceed the critical pressure of the refrigerant. Refrigerant oil for lubricating the compressor 2 is mixed in the refrigerant. A part of the refrigerant oil circulates in the cycle together with the refrigerant. Note that a refrigerant other than the HFC-based refrigerant may be adopted.

[0013] As shown in FIG. 1, the refrigeration cycle device 1 of this embodiment includes, as the constituent devices of the refrigeration cycle, a compressor 2, a radiator 3, a first expansion valve 4, an indoor evaporator 10, a second expansion valve 5, a chiller 6, and the like.

[0014] The compressor 2 in the refrigeration cycle device 1 draws in refrigerant and discharges the compressed refrigerant toward the radiator 3. The compressor 2 is an electric compressor whose refrigerant discharge capacity is controlled by a control signal output from an air conditioning control unit (not shown). The radiator 3 is connected to the downstream side of the refrigerant flow of the compressor 2. The radiator 3 is a heat exchanger that dissipates heat from the refrigerant by heat exchange with a gaseous or liquid heat transfer medium. A branching section BP1 is provided on the refrigerant outlet side of the radiator 3 to branch the refrigerant flow. A first expansion valve 4 is provided on one outlet side of this branching section BP1, and a second expansion valve 5 is provided on the other outlet side. The first expansion valve 4 and the second expansion valve 5 are pressure reducing devices that reduce the pressure of the refrigerant in liquid phase. The first expansion valve 4 and the second expansion valve 5 are composed of solenoid valves whose throttle opening can be controlled by a control signal output from an air conditioning control unit (not shown).

[0015] The first expansion valve 4 functions as a pressure reducing unit that reduces the amount of refrigerant flowing into the indoor evaporator 10 connected to the downstream side of the refrigerant flow of the first expansion valve 4, and also functions as a flow rate adjustment unit that adjusts the flow rate of refrigerant flowing into the indoor evaporator 10. The first expansion valve 4 in this embodiment is configured to be fully closed. The indoor evaporator 10 is a heat absorber that evaporates the refrigerant reduced in pressure by the first expansion valve 4 by exchanging heat with the blown air supplied to the vehicle interior. In other words, the indoor evaporator 10 is a cooling heat exchanger that cools the blown air, which is the fluid to be cooled, by the latent heat of vaporization of the refrigerant after it has passed through the first expansion valve 4. The indoor evaporator 10 in this embodiment is configured to improve the temperature distribution of the heat exchange section while suppressing oil accumulation. Details of the indoor evaporator 10 will be described later.

[0016] A confluence section BP2 is connected to the refrigerant outlet side of the indoor evaporator 10. This confluence section BP2 combines the flow of refrigerant discharged from the indoor evaporator 10 with the flow of refrigerant discharged from the chiller 6. The refrigerant suction side of the compressor 2 is connected to the refrigerant outlet side of the confluence section BP2.

[0017] The second expansion valve 5 functions as a pressure reducing unit that reduces the amount of refrigerant flowing into the chiller 6 connected to the downstream side of the refrigerant flow of the second expansion valve 5, and also functions as a flow rate adjustment unit that adjusts the flow rate of refrigerant flowing into the chiller 6. The second expansion valve 5 in this embodiment is configured to be fully closed.

[0018] Chiller 6 is a heat absorber that evaporates the refrigerant, which has been depressurized by the second expansion valve 5, by exchanging heat with a heat transfer medium used to regulate the temperature of on-board equipment such as batteries. The confluence section BP2 is connected to the refrigerant outlet side of chiller 6.

[0019] Next, the details of the indoor evaporator 10 of this embodiment will be explained with reference to Figures 2 to 6. The arrows labeled "front" and "rear" in Figure 2 indicate the front-rear direction Dx when the indoor evaporator 10 is mounted on a vehicle. The arrows labeled "one side" and "the other side" in Figures 2, 3, etc. indicate the width direction Dy when the indoor evaporator 10 is mounted on a vehicle. The arrows labeled "up" and "down" in Figure 2 indicate the up-down direction Dz when the indoor evaporator 10 is mounted on a vehicle.

[0020] As shown in Figures 2 and 3, the indoor evaporator 10 is composed of multiple tubes 20, fins 30, an upper tank section 40, and a lower tank section 50.

[0021] Multiple tubes 20 carry a refrigerant mixed with oil along the vertical direction Dz. Each tube 20 is made of a flat tube that forms a refrigerant passage with a flattened cross-section. Each tube 20 is arranged in a line with a predetermined spacing in the width direction Dy so that air can flow in the front-to-back direction Dx. An upper tank section 40 is connected to the upper end of each of the multiple tubes 20, and a lower tank section 50 is connected to the lower end. In addition, fins 30 are arranged between each tube 20 to promote heat transfer between the refrigerant and the air. The fins 30 are corrugated fins that are formed in a wave shape. In the indoor evaporator 10, each tube 20 and fin 30 constitute a "heat exchange section" that exchanges heat between the air and the refrigerant.

[0022] The upper tank section 40 is connected to the upper ends of multiple tubes 20. The upper tank section 40 has a refrigerant inlet 40a on one side in the width direction Dy and a refrigerant outlet 40b on the other side in the width direction Dy. The gas-liquid two-phase refrigerant, which has been depressurized and expanded by the first expansion valve 4, flows into the refrigerant inlet 40a. The refrigerant outlet 40b is connected to the refrigerant suction section of the compressor 2 via refrigerant piping (not shown), and the gas-phase refrigerant that has passed through the indoor evaporator 10 is returned to the compressor 2.

[0023] Specifically, the upper tank section 40 is composed of an upper cylindrical section 42 that forms a refrigerant flow passage 420, and an upper separator 44 that partitions the internal space of the upper cylindrical section 42 (i.e., the flow passage 420). The upper cylindrical section 42 extends along the width direction Dy. The upper cylindrical section 42 has a refrigerant inlet section 40a on one side in the width direction Dy and a refrigerant outlet section 40b on the other side in the width direction Dy. The upper separator 44 is positioned approximately in the center of the upper cylindrical section 42 in the width direction Dy. The upper separator 44 is sized to cover the entire cross-section of the flow passage 420 of the upper cylindrical section 42. The upper separator 44 divides the flow passage 420 of the upper cylindrical section 42 into an inlet distribution space 420a on one side in the width direction Dy and an outlet collection space 420b on the other side in the width direction Dy. The inlet distribution space 420a is a space that distributes the refrigerant flowing in from the refrigerant inlet 40a to the tube 20 on one side in the width direction Dy. The outlet collection space 420b is a space that collects the refrigerant flowing through the tube 20 on the other side in the width direction Dy.

[0024] The lower tank section 50 is connected to the lower ends of multiple tubes 20. The lower tank section 50 collects the refrigerant flowing through some of the tubes 20 and distributes the refrigerant to the other tubes 20.

[0025] Specifically, the lower tank section 50 is configured to include a lower cylindrical section 52 that forms a refrigerant flow passage 520. The lower cylindrical section 52 extends along the width direction Dy.

[0026] The flow passage 520 of the lower cylindrical section 52 is composed of an intermediate collection space 520a and an intermediate distribution space 520b. The intermediate collection space 520a is a collection space that collects the refrigerant flowing through some of the tubes 20 on one side in the width direction Dy. The intermediate distribution space 520b is a distribution space that distributes the refrigerant to the other tubes 20 on the other side in the width direction Dy. The refrigerant that flows into the intermediate collection space 520a flows into the intermediate distribution space 520b. Then, it is distributed from the intermediate distribution space 520b to each of the tubes 20 on the other side in the width direction Dy. In this case, if more refrigerant is distributed to the tubes 20 on one side in the width direction Dy than to the tubes 20 on the other side in the width direction Dy, the temperature distribution in the heat exchange section will expand.

[0027] Taking this into consideration, the lower tank section 50 is provided with a lower separator 60 that forms a throttling channel 61 smaller than the cross-sectional area of ​​the flow passage 520 of the lower cylindrical section 52. By throttling the refrigerant flow with the throttling channel 61, the velocity of the refrigerant flow is increased, and the refrigerant is sent to the back of the lower tank section 50, thereby improving the temperature distribution in the heat exchange section. In this embodiment, the lower separator 60 corresponds to the "separator" provided in the lower tank section 50.

[0028] The lower separator 60 is positioned at the boundary between the intermediate collection space 520a and the intermediate distribution space 520b. Specifically, the lower separator 60 is positioned within the lower tank section 50 at a location where it overlaps with the upper separator 44 in the vertical direction Dz.

[0029] As shown in Figure 4, the lower separator 60 covers the upper side of the flow passage 520 of the lower tank section 50 and is shaped to be spaced apart from the cylindrical bottom wall 521 that forms the bottom of the lower cylindrical section 52. Specifically, the lower separator 60 has a lower end portion that faces the arc-shaped cylindrical bottom wall 521 and extends linearly along the width direction Dy.

[0030] The throttling passage 61 is formed by the lower end of the lower separator 60 and the bottom wall 521 of the cylinder. In this embodiment, the throttling passage 61 is provided such that the position of the lower end of the passage hole forming the throttling passage 61 is aligned with the position of the bottom wall 521 of the cylinder. In other words, the throttling passage 61 is formed in the lower tank section 50 so that no irregularities that would cause oil to accumulate occur in the area where the lower separator 60 is located. In this embodiment, the throttling passage 61 not only functions as a throttling hole to improve the temperature distribution of the heat exchange section, but also functions as an oil return hole to suppress oil accumulation in the lower tank section 50.

[0031] In this configuration, the refrigeration cycle system 1 has multiple heat absorbers, such as an indoor evaporator 10 and a chiller 6, connected in parallel. The refrigeration cycle system 1 is configured to allow switching between a multi-operation mode, which supplies refrigerant to each of the multiple heat absorbers connected in parallel, and a single-operation mode, which supplies refrigerant to one of the multiple heat absorbers.

[0032] When the air conditioner switch (not shown) is turned on, the compressor 2 of the refrigeration cycle device 1 starts operating, and compressed high-pressure refrigerant in the gas phase is discharged from the compressor 2. The refrigerant discharged from the compressor 2 is cooled by the heat exchanger 3.

[0033] In the operating mode in which refrigerant is supplied to the indoor evaporator 10, the first expansion valve 4 is set to a throttled state, and the refrigerant that has passed through the heat exchanger 3 is depressurized by the first expansion valve 4. The refrigerant depressurized by the first expansion valve 4 is supplied to the indoor evaporator 10, where it absorbs heat from the air blown into the vehicle interior and evaporates. The refrigerant evaporated in the indoor evaporator 10, along with the oil, is drawn into the compressor 2 and compressed again.

[0034] Here, Figure 5 shows a portion of the cross-section of an evaporator CE, which is a comparative example of this embodiment. This evaporator CE differs from the indoor evaporator 10 of this embodiment in that a throttling hole PH is formed on the upper side of the lower separator LS.

[0035] As shown in Figure 5, in the comparative example evaporator CE, the refrigerant that flows into the intermediate collection space SP1 of the lower tank section LT is blown out to the intermediate distribution space SP2 through the throttling hole PH of the lower separator LS. However, the oil accumulated at the bottom of the intermediate collection space SP1 has difficulty moving to the intermediate distribution space SP2 due to the presence of the lower separator LS.

[0036] In contrast, in the indoor evaporator 10 of this embodiment, as shown in Figure 6, the throttled flow path 61 is formed below the lower separator 60, so that the oil accumulated at the bottom of the intermediate collection space 520a can easily move to the intermediate distribution space 520b via the throttled flow path 61.

[0037] On the other hand, in the operating mode when no refrigerant is flowing to the indoor evaporator 10, the first expansion valve 4 is set to a fully closed state, and the refrigerant that has passed through the heat exchanger 3 is supplied to the chiller 6 via the second expansion valve 5. The refrigerant supplied to the chiller 6 absorbs heat from the heat transfer medium and evaporates in the chiller 6. The refrigerant evaporated in the chiller 6 is drawn into the compressor 2 and compressed again.

[0038] In the operating mode where refrigerant is not flowing to the indoor evaporator 10, no refrigerant flows to the indoor evaporator 10. Therefore, if the lower tank section 50 has a structure that makes it easy for oil to accumulate, as in the comparative example evaporator CE, the amount of oil circulating in the cycle will decrease.

[0039] In contrast, the indoor evaporator 10 of this embodiment has a structure that makes it difficult for oil to accumulate in the lower tank section LT, so even in operating modes when refrigerant is not flowing to the indoor evaporator 10, it is possible to ensure the amount of oil circulating within the cycle.

[0040] The indoor evaporator 10 of this embodiment, as described above, is provided with a throttling channel 61 in the lower tank section 50. As a result, the refrigerant flow is restricted in the throttling channel 61, increasing the velocity of the refrigerant flow and making it easier for the refrigerant to reach the back of the lower tank section 50. This improves the temperature distribution in the heat exchange section of the indoor evaporator 10.

[0041] In addition, the indoor evaporator 10 of this disclosure is formed such that the throttling passage 61 is close to the bottom wall 521 of the lower cylindrical section 52 that forms the lower tank section 50. This makes it less likely for the movement of oil to be restricted by the lower separator 60 provided in the lower tank section 50, and thus suppresses oil stagnation in the indoor evaporator 10.

[0042] Here, Figure 7 shows a comparison of the cooling performance at high load and the oil circulation rate at low load in the refrigeration cycle device 1 when using the indoor evaporator 10 of the present invention and when using the evaporator CE of the comparative example.

[0043] As shown in the upper part of Figure 7, the cooling performance of the refrigeration cycle device 1 tends to decrease under high load as the amount of oil filled increases. On the other hand, from the standpoint of protecting the compressor 2, as shown in the lower part of Figure 7, it is necessary to fill the oil so that the oil circulation rate within the cycle under low load is equal to or greater than a predetermined specified value.

[0044] As mentioned above, the comparative evaporator CE has a structure that makes it easy for oil to accumulate in the lower tank section LT. As a result, the oil circulation rate during the cycle at low loads decreases. When using the comparative evaporator CE, if the oil circulation rate at low loads is to be increased to above the specified value, for example, the amount of oil sealed in may be increased. However, while increasing the amount of oil sealed in can protect the compressor 2, it reduces the cooling performance at high loads.

[0045] Alternatively, as shown in Figure 8, it is conceivable to implement oil return control by intermittently changing the throttle opening of the expansion valve to suppress oil accumulation in the lower tank section LT. However, this increases the power consumption of the compressor 2 and raises the temperature of the air blown into the vehicle cabin.

[0046] Thus, previous measures such as increasing the amount of oil sealed in and implementing oil return control all contribute to a decrease in the cooling performance of the refrigeration cycle.

[0047] In contrast, the indoor evaporator 10 of this invention has a structure that makes it difficult for oil to accumulate in the lower tank section 50, so it is possible to reduce the amount of oil to be sealed in, or to reduce or eliminate the frequency of oil return control. Therefore, the indoor evaporator 10 of this invention can improve the temperature distribution of the heat exchange section while suppressing oil accumulation.

[0048] Furthermore, the indoor evaporator 10 of this embodiment has the following features. (1) In this embodiment, the throttling passage 61 is provided such that the position of the lower end of the passage hole forming the throttling passage 61 is aligned with the position of the bottom wall 521 of the cylinder. This eliminates the restriction of oil movement by the lower separator 60 and reduces oil stagnation in the lower tank section 50 of the indoor evaporator 10.

[0049] (2) The flow passage 520 of the lower tank section 50 includes an intermediate collection space 520a for collecting the refrigerant flowing through some of the tubes 20 and an intermediate distribution space 520b for distributing the refrigerant collected in the intermediate collection space 520a to the other tubes 20. The lower separator 60 is provided at the boundary between the intermediate collection space 520a and the intermediate distribution space 520b. This makes it easier for the oil in the intermediate collection space 520a to move to the intermediate distribution space 520b via the throttling passage 61, thereby effectively suppressing the accumulation of oil in the intermediate collection space 520a.

[0050] (Modification of the first embodiment) In the first embodiment, the lower separator 60 has a shape in which the lower end portion facing the arc-shaped cylindrical bottom wall 521 extends linearly along the width direction Dy, but is not limited to this. The lower separator 60 may have a shape in which, for example, as shown in Figure 9, an elongated notch is formed extending upward from the lower end portion facing the cylindrical bottom wall 521.

[0051] As in the first embodiment, it is desirable that the aperture channel 61 be provided such that the lower end of the channel hole forming the aperture channel 61 aligns with the position of the bottom wall 521 of the cylinder, but this is not required. Also, the aperture channel 61 may be formed by a through hole or the like, rather than a notch formed in the lower separator 60. These points are also true in subsequent embodiments.

[0052] In the first embodiment, the lower separator 60 is provided at a position that forms the boundary between the intermediate collection space 520a and the intermediate distribution space 520b, but is not limited to this. The lower separator 60 may also be provided in the intermediate distribution space 520b. This also makes it easier for the oil in the intermediate collection space 520a to move to the intermediate distribution space 520b via the throttling passage 61, thereby effectively suppressing the accumulation of oil in the intermediate collection space 520a.

[0053] (Second Embodiment) Next, a second embodiment will be described with reference to Figures 10 and 11. In this embodiment, the differences from the first embodiment will be mainly described.

[0054] As shown in Figures 10 and 11, the lower separator 60 of this embodiment has a throttling hole 62 formed in a portion above the throttling passage 61, which is smaller than the cross-sectional area of ​​the flow passage 520 of the lower tank section 50. In other words, the lower tank section 50 of this embodiment is provided with a throttling passage 61 as an oil return hole to suppress oil stagnation in the lower tank section 50, and separately from the throttling passage 61, a throttling hole 62 is provided to improve the temperature distribution of the heat exchange section. The throttling hole 62 is formed in the lower separator 60 and consists of a through hole with a circular cross-section. Note that the throttling hole 62 is not limited to a through hole with a circular cross-section, but may also consist of a through hole with an elliptical or polygonal cross-section, for example.

[0055] In the lower tank section 50 configured in this way, the gas-liquid two-phase refrigerant in the intermediate collection space 520a flows through the throttling hole 62 to the intermediate distribution space 520b, and the oil in the intermediate collection space 520a flows through the throttling passage 61 below the throttling hole 62 to the intermediate distribution space 520b.

[0056] Other aspects are the same as in the first embodiment. The indoor evaporator 10 of this embodiment can obtain the same effects as in the first embodiment, which are achieved through a configuration common to or equivalent to that of the first embodiment.

[0057] Furthermore, the indoor evaporator 10 of this embodiment has the following features. (1) The lower separator 60 has a throttling hole 62 formed in a portion above the throttling passage 61 that is smaller than the cross-sectional area of ​​the flow passage 520 of the lower tank section 50. In other words, the lower separator 60 of this embodiment has a configuration in which a throttling passage 61 for returning oil and a throttling hole 62 for increasing the velocity of the refrigerant flow are provided separately. With this, the size and shape of the throttling passage 61 and the throttling hole 62 can be set individually. For example, a throttling passage 61 can be set to a size and shape suitable for returning oil, or a throttling hole 62 can be set to a size and shape suitable for increasing the velocity of the refrigerant flow.

[0058] (Modified version of the second embodiment) In the embodiments described above, an example was given in which the aperture channel 61 is composed of a single channel hole, but the invention is not limited to this. The aperture channel 61 may be composed of multiple channel holes 61a, 61b, 61c, for example, as shown in Figure 12. The same applies to the aperture hole 62.

[0059] (Third embodiment) Next, the third embodiment will be described with reference to Figures 13 to 15. In this embodiment, the differences from the first embodiment will be mainly described.

[0060] As shown in Figure 13, the lower tank section 50 of this embodiment is provided with a guide section 63 that guides the oil or refrigerant that has passed through the throttling passage 61 upward from the lower end side of the cylindrical bottom wall 521 of the lower tank section 50. This guide section 63 is provided to spray the oil that has passed through the throttling passage 61 upward towards the lower end of the tube 20. The guide section 63 is composed of an inclined section that slopes diagonally upward from the position where the throttling passage 61 is formed toward the intermediate distribution space 520b.

[0061] As shown in Figures 14 and 15, the guide portion 63 of this embodiment is composed of a part located on the lower side of the lower separator 60. Specifically, the lower separator 60 is composed of a plate material formed to cover the entire flow passage 520 of the lower tank portion 50. The guide portion 63 is formed by cutting out a semicircular shape from the lower part of the plate material constituting the lower separator 60, leaving a part of the portion in contact with the cylindrical bottom wall 521, and then pushing down this cut-out piece so that it is inclined toward the intermediate distribution space 520b.

[0062] In the lower tank section 50 configured in this way, the oil and refrigerant in the intermediate collection space 520a flow through the throttling passage 61 to the intermediate distribution space 520b, and then are ejected upward by the guide section 63 towards the lower end of the tube 20.

[0063] Other aspects are the same as in the first embodiment. The indoor evaporator 10 of this embodiment can obtain the same effects as in the first embodiment, which are achieved through a configuration common to or equivalent to that of the first embodiment.

[0064] Furthermore, the indoor evaporator 10 of this embodiment has the following features. (1) The lower tank section 50 is provided with a guide section 63 that guides the oil or refrigerant that has passed through the throttling passage 61 upward from the lower end of the bottom wall 521 of the cylinder. This allows the oil or refrigerant that has passed through the throttling passage 61 to be sprayed out along the guide section 63 toward the lower end of the tube 20, thereby effectively suppressing the accumulation of oil in the lower tank section 50.

[0065] (Modified version of the third embodiment) In the third embodiment, the lower tank section 50 has a throttling passage 61 that serves both as a throttling hole to improve the temperature distribution of the heat exchange section and as an oil return hole to suppress oil stagnation in the lower tank section 50, but is not limited to this. The lower tank section 50 may also be configured such that, for example, as shown in Figure 16, a throttling passage 61 for returning oil and a throttling hole 62 for increasing the velocity of the refrigerant flow are provided separately.

[0066] In this embodiment, the lower tank section 50 is provided such that the guide section 63 overlaps with the formation position of the throttling flow path 61, but it is not limited to this. In the lower tank section 50, for example, the guide section 63 may be provided in the intermediate distribution space 520b. Also, the lower tank section 50 may have multiple guide sections 63. These are also the case in subsequent embodiments.

[0067] (Fourth Embodiment) Next, the fourth embodiment will be described with reference to Figure 17. In this embodiment, the differences from the third embodiment will be mainly described.

[0068] As shown in Figure 17, the guide portion 63 in this embodiment is formed by a portion of the lower tank portion 50 that forms the throttling channel 61, which is recessed upward. In other words, the guide portion 63 is formed by a portion of the cylindrical bottom wall 521 that is raised upward.

[0069] Other aspects are the same as in the third embodiment. The indoor evaporator 10 of this embodiment can obtain the same effects as in the third embodiment, which are achieved through a configuration common to or equivalent to that of the third embodiment.

[0070] (Modified version of the fourth embodiment) In the fourth embodiment, a guide portion 63 is formed by raising a part of the cylindrical bottom wall 521 of the lower tank portion 50, but the invention is not limited to this, and the guide portion 63 may be composed of a part other than the lower tank portion 50 or the lower separator 60.

[0071] (Other embodiments) While representative embodiments of this disclosure have been described above, this disclosure is not limited to the embodiments described above and can be modified in various ways, for example, as follows.

[0072] In the above-described embodiment, the lower tank portion 50 of the indoor evaporator 10 is exemplified as having an angular shape at the upper part and a rounded shape at the lower part, but it is not limited to this. For example, the lower tank portion 50 may be entirely rectangular or cylindrical in shape.

[0073] The above-described embodiment illustrates a heat exchanger in which the tubes 20 are arranged in a single row in the front-to-back direction Dx as the indoor evaporator 10, but the indoor evaporator 10 is not limited to this. The indoor evaporator 10 may be composed of, for example, a heat exchanger in which the tubes 20 are arranged in multiple rows in the front-to-back direction Dx.

[0074] In the above-described embodiment, the indoor evaporator 10 was exemplified as a heat exchanger that exchanges heat between the refrigerant and the air supplied to the vehicle interior, but the indoor evaporator 10 is not limited to this. The indoor evaporator 10 may be composed of a heat exchanger that exchanges heat between the refrigerant and a fluid other than air, for example. Also, the upper tank section 40 of the indoor evaporator 10 is not essential and may be omitted.

[0075] In the embodiments described above, an example was given in which the indoor evaporator 10 of this disclosure is applied to a refrigeration cycle system 1 in which the indoor evaporator 10 and the chiller 6 are arranged in parallel within the cycle. However, the application of the indoor evaporator 10 is not limited to this. The indoor evaporator 10 can also be applied to a refrigeration cycle system 1 equipped with a single "evaporator" or a refrigeration cycle system 1 equipped with multiple "evaporators," for example.

[0076] In the embodiments described above, it goes without saying that the elements constituting the embodiments are not necessarily essential, except in cases where they are explicitly stated to be essential or where they are clearly considered essential in principle.

[0077] In the embodiments described above, if numerical values ​​such as the number, numerical values, quantities, or ranges of the components of the embodiment are mentioned, the embodiment is not limited to those specific numbers unless explicitly stated as particularly essential or clearly limited to a specific number in principle.

[0078] In the embodiments described above, when referring to the shape, positional relationships, etc. of the components, the definition is not limited to those shapes, positional relationships, etc., unless otherwise specifically stated or when the definition is fundamentally limited to a particular shape, positional relationship, etc. [Explanation of symbols]

[0079] 10. Indoor evaporator (evaporator) 20 tubes 50 Lower tank section 52 Cylinder part 520 Distribution path 520a Intermediate set space 520b Intermediate distribution space 521 Bottom wall of the cylinder 60 Separators 61 Aperture channel

Claims

1. An evaporator applied to a vapor compression type refrigeration cycle system, Multiple tubes (20) through which the oil-mixed refrigerant flows in an up-and-down direction, The system includes a lower tank section (50) connected to the lower end of a plurality of tubes, which collects the refrigerant flowing through some of the tubes and distributes the refrigerant to the other tubes, The aforementioned lower tank section is A cylindrical portion (52) that forms a refrigerant flow passage (520), It includes a separator (60) that forms a throttling channel (61) smaller than the cross-sectional area of ​​the flow passage in the cylindrical portion, The aforementioned throttling channel is formed in close proximity to the bottom wall (521) of the cylindrical section of the evaporator.

2. The evaporator according to claim 1, wherein the separator has a diaphragm hole (62) formed in a portion above the diaphragm flow path that is smaller than the cross-sectional area of ​​the flow path.

3. The evaporator according to claim 1 or 2, wherein the throttling channel is provided such that the position of the lower end of the channel hole forming the throttling channel is aligned with the position of the bottom wall of the cylinder.

4. The evaporator according to claim 1 or 2, wherein the lower tank section is provided with a guide section (63) that guides the refrigerant that has passed through the throttling passage to a position above the lower end of the bottom wall of the cylinder.

5. The flow passage includes a collection space (520a) for collecting the refrigerant flowing through some of the tubes and a distribution space (520b) for distributing the refrigerant collected in the collection space to the other tubes. The evaporator according to claim 1 or 2, wherein the separator is located at a position that forms the boundary between the collection space and the distribution space, or is provided in the distribution space.

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