JP5101221B2 - Air conditioner for vehicles - Google Patents

Description

  The present invention relates to a vehicle air conditioner including a unit case that guides air blown from a blower unit to an evaporator inlet flow path through a diffuser section and distributes the air to the evaporator.

  In the unit case forming the air flow path, an evaporator and a heater core are sequentially arranged along the air flow direction, and the ratio of the amount of air cooled by the evaporator and the amount of air passing through the heater and the amount of bypass is determined by the air mix damper. The air conditioning unit that draws in outside air or inside air from the air blowing unit that is offset in the left-right direction of the vehicle with respect to the air conditioning unit (HVAC unit) that controls the air temperature that is blown into the vehicle through a plurality of outlets. A vehicular air conditioner configured to blow air is put into practical use.

  In the above vehicle air conditioner, the air blown from the blower unit is guided to the evaporator inlet flow path through the diffuser portion formed in the unit case, and the direction of the air is changed in the evaporator inlet flow path and distributed to the evaporator. Will be. In such a vehicle air conditioner, the surface facing the evaporator core surface of the unit case forming the evaporator inlet flow path is configured in a staircase shape along the air inflow direction, and the air flow direction is changed on the step surface. Patent Document 1 discloses a vehicle air conditioner in which an air flow is caused to flow through the entire core surface of an evaporator so as to make the wind speed distribution uniform.

  Further, Patent Document 2 discloses that a predetermined gap is formed between a portion of the diffuser portion of the unit case that faces the enlarged portion of the evaporator core surface and protrudes toward the evaporator inlet flow path and between the enlarged portion of the evaporator core surface. The air flow changing section having the air flow is provided so that the air flow is forcibly directed to the core surface of the evaporator and the air velocity distribution passing through the core surface is made uniform without causing an increase in noise generated during blowing. A vehicle air conditioner is shown.

JP 2002-144848 A Japanese Patent Laid-Open No. 2003-21936

  However, in the vehicle air conditioner in which the air blown from the air blowing unit described above is guided to the evaporator inlet flow path through the diffuser section and is changed in direction to flow to the evaporator, the diffuser in which the air flow path is enlarged In the section, noise is generated due to pressure fluctuation due to the separation flow of the air flow. Although the separation flow of the air flow at the diffuser portion in the unit case is designed to be suppressed as much as possible, it cannot be completely eliminated. As shown in FIG. 10, the noise is a surface of the unit case in which the sound wave SW due to the self-excited vibration of the separation vortex SV generated by the separation flow in the diffuser portion 22 faces the air inflow direction of the unit case forming the evaporator inlet flow path. This is considered to be noise in a specific frequency region due to reflection at 23 and the frequency of the reflected wave and the frequency of self-excited vibration resonate.

  The vehicle air conditioners shown in Patent Documents 1 and 2 are provided with an air flow changing portion in an evaporator inlet flow channel of an air conditioning unit into which an air flow from a blower unit flows, thereby facilitating a change in direction of the air flow. The wind speed distribution of the air flow passing through the evaporator can be made uniform without increasing noise. However, it is not possible to suppress noise caused by pressure fluctuation due to the separation flow of the air flow in the diffuser portion of the unit case. Therefore, the noise in the specific frequency region due to the self-excited vibration of the separation vortex generated in the diffuser portion has not yet been eliminated.

  The present invention has been made in view of such circumstances, and provides a vehicle air conditioner capable of reducing noise in a specific frequency region due to self-excited vibration of a separation vortex generated in a diffuser portion of a unit case. The purpose is to do.

In order to solve the above problems, the vehicle air conditioner of the present invention employs the following means.
That is, the vehicle air conditioner according to the present invention includes a blower unit that sucks outside air or inside air and blows the air downstream, and an air conditioning unit that regulates the temperature of the air blown from the blower unit and blows it into the vehicle interior. The air conditioning unit includes a unit case that guides the air blown from the blower unit to the evaporator inlet flow path through the diffuser portion and distributes the air from the evaporator inlet flow path to the evaporator. Reflection direction change that changes the reflection direction of the sound wave by the self-excited vibration of the separation vortex generated in the diffuser part facing the diffuser part on the surface of the unit case that forms the evaporator inlet flow channel that faces the air inflow direction A part is comprised by the said opposing surface itself of the said unit case, It is characterized by the above-mentioned .

In a vehicle air conditioner equipped with a unit case that directs the air blown from the blower unit to the evaporator inlet flow path through the diffuser and circulates it to the evaporator, the sound waves generated by the self-excited vibration of the separation vortex generated in the diffuser Reflected by the surface of the unit case that forms the evaporator inlet flow channel facing the air inflow direction, the frequency of the reflected wave and the frequency of the self-excited vibration resonate to generate noise in a specific frequency region.
According to the present invention, the diffuser portion is formed by the reflection direction changing portion configured by the facing surface itself provided facing the diffuser portion on the surface facing the air inflow direction of the unit case forming the evaporator inlet flow path. Since the reflection direction of the sound wave due to the self-excited vibration of the separation vortex generated in the above can be changed, the noise in the resonance mode due to the standing wave in the specific frequency region can be suppressed. Therefore, it is possible to reduce noise caused by the separation flow generated in the diffuser portion of the unit case.

  Furthermore, the vehicle air conditioner according to the present invention is characterized in that, in the above-described vehicle air conditioner, the sound wave reflection direction changing portion is configured by a wedge-shaped uneven surface.

  According to the present invention, it is possible to change the direction in which sound waves are reflected by the self-excited vibration of the separation vortex generated in the diffuser portion by the wedge surface of the wedge-shaped uneven surface. For this reason, the noise of the resonance mode by the standing wave of a specific frequency area | region can be suppressed, and the noise resulting from the peeling flow which generate | occur | produces in the diffuser part of a unit case can be reduced.

  Furthermore, the vehicle air conditioner according to the present invention is characterized in that, in the above-described vehicle air conditioner, the sound wave reflection direction changing portion is configured by a curved surface.

  According to the present invention, it is possible to change the reflection direction of the sound wave by the self-excited vibration of the separation vortex generated in the diffuser portion by the curved surface. For this reason, the noise of the resonance mode by the standing wave of a specific frequency area | region can be suppressed, and the noise resulting from the peeling flow which generate | occur | produces in the diffuser part of a unit case can be reduced.

  Furthermore, the vehicle air conditioner according to the present invention is characterized in that, in the above vehicle air conditioner, the sound wave reflection direction changing unit is configured by an inclined surface inclined with respect to a surface orthogonal to the air inflow direction. And

  According to the present invention, the reflection direction of the sound wave due to the self-excited vibration of the separation vortex generated in the diffuser portion can be changed by the inclined surface inclined with respect to the surface orthogonal to the air inflow direction. For this reason, the noise of the resonance mode by the standing wave of a specific frequency area | region can be suppressed, and the noise resulting from the peeling flow which generate | occur | produces in the diffuser part of a unit case can be reduced.

  Furthermore, in the vehicle air conditioner according to the present invention, a surface of the unit case that forms the evaporator inlet flow path that faces the core surface of the evaporator is along the air inflow direction. The stepped surface is a stepped surface that faces the air inflow direction of the stepped surface, and changes the reflection direction of the sound wave by the self-excited vibration of the separation vortex generated in the diffuser portion facing the diffuser portion. A reflection direction changing unit is provided.

  According to the present invention, since the surface facing the evaporator core surface in the unit case forming the evaporator inlet flow path is a stepped surface along the air inflow direction, the air flow direction is changed by the step surface. Can be promoted. Thereby, an air flow can be made to flow uniformly over the whole core surface of an evaporator, and a wind speed distribution can be made uniform. Moreover, the reflection direction of the sound wave by the self-excited vibration of the separation vortex generated in the diffuser portion can be changed by the reflection direction changing portion provided on the step surface of the step shape surface so as to face the diffuser portion. Thereby, the noise of the resonance mode by the standing wave of a specific frequency area | region can be suppressed. Therefore, it is possible to reduce noise caused by the separation flow generated in the diffuser portion of the unit case.

  Furthermore, in the vehicle air conditioner according to the present invention, the stepped surface of the stepped surface is provided in a plurality of steps along the air inflow direction, and the reflection direction changing unit is provided on each stepped surface. Is provided.

  According to the present invention, the reflection direction changing portion is provided on each step surface of the step shape surface provided in a plurality of steps along the air inflow direction, and the sound wave generated by the self-excited vibration of the separation vortex generated in the diffuser portion by each step surface. The reflection direction of can be changed. For this reason, the noise of the resonance mode by the standing wave of a specific frequency area | region can be suppressed on each step surface, and the noise resulting from the peeling flow which generate | occur | produces in the diffuser part of a unit case can be reduced.

According to the vehicle air conditioner of the present invention, the diffuser portion is formed by the reflection direction changing portion configured by the facing surface itself provided facing the diffuser portion on the surface on which the sound wave due to the self-excited vibration of the separation vortex is reflected. It is possible to change the reflection direction of the sound wave due to the self-excited vibration of the separation vortex generated in the case, so that the resonance mode noise caused by the standing wave in the specific frequency range is suppressed, resulting from the separation flow generated in the diffuser part of the unit case Noise can be reduced.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
FIG. 1 shows an external perspective view of a vehicle air conditioner 1 according to the first embodiment of the present invention. The vehicle air conditioner 1 sets the air blown from the blower unit 2 connected to the downstream side of the blower unit 2 and the blower unit 2 that sucks the outside air from the outside of the vehicle or the inside air from the passenger compartment and blows it downstream. It is composed of an air conditioning unit (HVAC unit) 3 that regulates the temperature and blows it into the passenger compartment.

  The blower unit 2 includes a centrifugal blower 4 provided with an impeller 7 (see FIG. 2) driven by a motor 6 in a casing 5, and an inside / outside air switching device connected to an air suction port provided on one surface of the casing 5. 8. The inside / outside air switching device 8 includes an inside / outside air switching case 10 having an outside air introduction port 9 opened on the upper surface and an inside air introduction port (not shown) opened on the side surface adjacent to the inside / outside air switching case 10. The inside / outside air switching damper (not shown) is configured, and either outside air from the outside of the vehicle or inside air from the vehicle interior can be selectively introduced.

  The air conditioning unit 3 includes a unit case 11 that is divided into a plurality of parts, and an air flow path 12 (see FIG. 2) that is formed by the unit case 11 along the front-rear direction of the vehicle includes a refrigerating cycle that is not shown. An evaporator 13 (see FIG. 2) that evaporates the refrigerant and cools the air, and a heater core (not shown) that heats the air with hot water circulated from the vehicle travel engine are sequentially disposed in the front and rear, and the evaporator 13. An air mix damper (not shown) that adjusts the ratio of the amount of air that passes through the heater core and the amount that bypasses the air, and temperature control devices such as face doors, differential doors, and foot doors installed at a plurality of air outlets are known. It is accommodated and installed as follows.

  The air conditioning unit 3 is provided with face air outlets 14A and 14B, differential air outlets 15A and 15B, foot air outlets 16A and 16B, and a rear seat duct 17, and these air air outlets 14A and 14A are provided. 14B, 15A, 15B, 16A, 16B and the rear seat duct 17 are selectively opened and closed through the face door, the differential door, and the foot door operated in conjunction with each other, whereby the selected air blowing The temperature-controlled air is configured to be blown out from the mouth into the passenger compartment.

  As shown in FIG. 1, the air blower unit 2 and the air conditioning unit 3 are integrally assembled, and the air conditioning unit 3 is positioned in a substantially central portion in the left-right direction of the vehicle in the space inside the instrument panel in front of the vehicle interior. Then, the blower unit 2 is installed in a state offset to the passenger seat side. Therefore, as shown in FIG. 2, the air blown from the blower unit 2 along the left-right direction of the vehicle is redirected in the front-rear direction of the vehicle in the evaporator inlet passage 21 formed in front of the evaporator 13. It will flow into the evaporator 13.

  Further, as shown in FIG. 3, the casing 5 of the blower unit 2 and the unit case 11 of the air conditioning unit 3 have different height direction dimensions. An enlarged diffuser portion 22 is formed. The diffuser portion 22 and the evaporator inlet flow channel 21 in which the air flow channel is enlarged are formed integrally with the unit case 11, but may be integrally formed or divided separately, or a part thereof is a blower unit. The two casings 5 may also be used.

  Further, on the surface 23 of the unit case 11 that forms the evaporator inlet passage 21 that faces the inflow direction of the air flowing in from the blower unit 2, the separation generated by the separation flow in the diffuser portion 22 where the air passage is enlarged. A reflection direction changing unit 24 that changes the reflection direction of the sound wave by the self-excited vibration of the vortex is provided. The reflection direction changing unit 24 may have any configuration as long as the reflection direction can be changed so that the reflected wave of the sound wave incident on the facing surface 23 is reflected in a direction different from the incident direction. In the present embodiment, the reflection direction changing unit 24 is configured by a wedge-shaped uneven surface body 25 protruding toward the flow path side of the evaporator inlet flow path 21 as shown in FIG.

With the configuration described above, according to the present embodiment, the following operational effects can be obtained.
The outside air or the inside air sucked from the outside air introduction port 9 or the inside air introduction port (not shown) of the inside / outside air switching device 8 of the blower unit 2 is boosted by the impeller 7 of the blower 4 and sent to the air conditioning unit 3 on the downstream side. Is done. This air flow is changed in the front-rear direction by the evaporator inlet passage 21 and flows into the air passage 12 on the air conditioning unit 3 side, and is cooled in the process of passing through the evaporator 13. A part of the cooling air is circulated to the heater core (not shown) by an air mix damper (not shown), and the rest bypasses the heater core and is mixed again in the air mix area downstream of the heater core. The temperature-controlled air thus adjusted to the set temperature is the face air outlets 14A and 14B, the differential air outlets 15A and 15B, the foot air outlets 16A and 16B, and the rear seat duct provided on the downstream side of the air mix area. The selected one or a plurality of 17 are blown out into the passenger compartment and used for air conditioning in the passenger compartment.

  During this time, when the air flow blown from the blower unit 2 to the air conditioning unit 3 flows into the evaporator inlet flow path 21, a separation flow occurs in the diffuser portion 22 where the air flow path expands, and the pressure fluctuation due to this separation flow Causes noise. As shown in FIG. 10, this noise is caused by the sound wave SW generated by the self-excited vibration of the separation vortex SV generated by the separation flow in the diffuser portion 22 in the air inflow direction of the unit case 11 that forms the evaporator inlet passage 21. It is considered as noise in a specific frequency region that is reflected by the opposing surface 23 and the frequency of the reflected wave resonates with the frequency of self-excited vibration.

Here, the feedback frequency f (Hz) in the specific frequency region can be expressed by the following equation.
f (Hz) = 1 / (2L / a)
In the above formula, L is the distance (m) from the location where the separation vortex SV of the diffuser portion 22 is generated to the facing surface 23, and a is the speed of sound (a = 340 m / sec).
In general, the dimension in the length direction of the evaporator 13 is considered to be about 30 to 40 cm. Therefore, when the distance L is set to 34 cm, for example, the feedback frequency f (Hz) can be calculated from the above equation by f = 1 / (2 * 0.34 / 340) = 500 (Hz). Therefore, the above-mentioned noise is considered to be generated by a sound wave in the vicinity of 500 Hz becoming a standing wave and in resonance with the self-excited vibration of the separation vortex SV.

  However, in the present embodiment, a wedge-shaped concavo-convex surface body 25 is provided as the reflection direction changing unit 24 that changes the reflection direction of the sound wave SW on the facing surface 23 where the sound wave SW due to the self-excited vibration of the separation vortex SV is reflected. By this uneven surface body 25, the reflected wave of the sound wave SW incident on the wedge surface is reflected in a direction different from the incident direction. As a result, the noise in the resonance mode due to the standing wave in the specific frequency region near 500 Hz can be suppressed. Therefore, it is possible to reduce noise caused by the separation flow generated in the diffuser portion 22 of the unit case 11.

  FIG. 8 is a graph showing the relationship between the pressure (no dimension) and the frequency (Hz) in the case without the wedge-shaped uneven surface body 25 (broken line) and in the case with the wedge-shaped uneven surface body 25 (solid line). is there. This graph is a measurement of pressure fluctuation on the wall surface and not noise, but the air flow in the air conditioning unit 3 is low speed, and in that case, the pressure on the wall surface is a noise factor. Fluctuations will be involved. Although it cannot be said that the pressure fluctuation and the sound are in a proportional relationship, the noise data are linked to each other, and it is considered that the noise increases when the pressure fluctuation is large. From the graph of FIG. 8, it can be seen that the pressure around 500 Hz is reduced, and it is understood that the noise is reduced accordingly.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIGS. 4 and 9.
In the present embodiment, the configuration of the reflection direction changing unit 24 is different from the first embodiment described above. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In the present embodiment, the reflection direction changing unit 24 is configured by a curved curved body 26 that protrudes toward the flow path side of the evaporator inlet flow path 21 as shown in FIG.

By providing the curved curved surface body 26 as described above, the reflected wave of the sound wave SW incident on the curved surface can be reflected in a direction different from the incident direction. Therefore, similarly to the first embodiment, it is possible to suppress the noise in the resonance mode due to the standing wave in the specific frequency region near 500 Hz and reduce the noise caused by the separation flow generated in the diffuser portion 22 of the unit case 11. it can. Incidentally, FIG. 9 is a diagram showing the relationship between the pressure (non-dimensional) and the frequency (Hz) when there is no curved curved body 26 (broken line) and when there is a curved curved body 26 (solid line). A graph similar to FIG. 8 is shown. As is apparent from this graph, it is understood that the pressure around 500 Hz is greatly reduced, and the noise is correspondingly reduced.
From the comparison result between FIG. 8 and FIG. 9, it can be seen that the curved curved body 26 gives better results than the wedge-shaped uneven surface body 25.

In addition to the above-described embodiment, the reflection direction changing unit 24 is inclined with respect to a plane orthogonal to the air inflow direction protruding to the flow channel side of the evaporator inlet flow channel 21 as shown in FIG. It can also be configured by an inclined surface body 27 having two surfaces.
Furthermore, the facing surface 23 itself of the unit case 11 is a processed surface as shown in FIGS. 4C, 4D, 4E, and 4F, and the reflected direction changing portion 24 is formed by the processed surface. It may be configured. For example, FIG. 4C shows an example in which the facing surface 23 of the unit case 11 is a curved projecting surface 28 that projects outward in a curved shape. 4D shows an example in which the opposing surface 23 of the unit case 11 is an inclined protruding surface 29 composed of two inclined surfaces protruding outward, and FIGS. ) Shows an example in which the opposing surface 23 of the unit case 11 is inclined surfaces 30 and 31 inclined obliquely upward or obtusely or acutely with respect to a surface orthogonal to the air inflow direction.

  Reflected by the inclined surface body 27, the curved protruding surface 28, the inclined protruding surface 29, and the inclined surfaces 30, 31 as shown in FIGS. 4 (B), (C), (D), (E), and (F). Also by configuring the direction changing unit 24, the reflected wave of the sound wave SW incident on each surface can be reflected in a direction different from the incident direction. Therefore, similarly to the first embodiment, it is possible to suppress the noise in the resonance mode due to the standing wave in the specific frequency region near 500 Hz and reduce the noise caused by the separation flow generated in the diffuser portion 22 of the unit case 11. it can.

[Third Embodiment]
Next, a third embodiment of the present invention will be described with reference to FIG.
In the present embodiment, the configuration of the reflection direction changing unit 24 is different from the first embodiment described above. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In the present embodiment, the surface facing the core surface 13A of the evaporator 13 forming the evaporator inlet passage 21 has a plurality of step surfaces 42 along the air inflow direction, as shown in FIG. The surface 41 is formed by a shape. Each step surface 42 is provided with a reflection direction changing section 24 as shown in FIG. 5B or 5C. That is, each step surface 42 protrudes in a curved shape as shown in FIG. 5 (B), as shown in FIG. 5 (B), or as an inclined protruding surface 43 composed of two inclined surfaces, or as shown in FIG. 5 (C). The curved projecting surface 44 is used.

  As described above, the surface facing the core surface 13A of the evaporator 13 forming the evaporator inlet flow path 21 is a stepped surface 41 along the air inflow direction, so that the air blowing unit is operated by each step surface 42. The direction change of the airflow blown from 2 can be promoted. As a result, the air flow can be made to flow substantially uniformly over the entire core surface 13A of the evaporator 13 to make the wind velocity distribution uniform. Further, the reflection direction changing portion 24 provided on the plurality of step surfaces 42 of the stepped surface 41, that is, the inclined protrusion surface 43 or the curved protrusion surface 44, is caused by self-excited vibration of the separation vortex SV generated in the diffuser portion 22. The reflection direction of the sound wave SW can be changed. Thereby, the noise of the resonance mode by the standing wave of a specific frequency area | region can be suppressed, and the noise resulting from the peeling flow which generate | occur | produces in the diffuser part 22 of the unit case 11 can be reduced.

[Reference example]
Next, a reference example of the present invention will be described with reference to FIG.
The present embodiment is different from the first embodiment described above in that a porous reflecting plate 50 is provided in the middle of the evaporator inlet channel 21. Since other points are the same as those in the first embodiment, description thereof will be omitted.
As shown in FIG. 6, this reference example has a configuration in which a porous reflector 50 is provided in a direction that intersects the air inflow direction at a midway position in the air inflow direction of the evaporator inlet passage 21.

  As described above, by providing the porous reflection plate 50 in the middle of the evaporator inlet channel 21, a part of the sound wave SW due to the self-excited vibration of the separation vortex SV generated in the diffuser portion 22 is reflected by the porous reflection plate 50. The remaining part that has passed through the porous reflector 50 is reflected and attenuated by the opposing surface 23 in multiple stages. Thereby, the noise of the resonance mode by the standing wave of the specific frequency area | region of 500 Hz vicinity can be suppressed. Therefore, it is possible to reduce noise caused by the separation flow generated in the diffuser portion 22 of the unit case 11.

[Second Reference Example]
Next, a second reference example of the present invention will be described with reference to FIG.
The present reference example is different from the first embodiment described above in that a sound absorbing material 60 is provided on the surface 23 of the evaporator inlet passage 21 facing the air inflow direction. Since other points are the same as those in the first embodiment, description thereof will be omitted.
As shown in FIG. 7, the present reference example has a configuration in which a sound absorbing material 60 is provided on the surface 23 of the unit case 11 that forms the evaporator inlet flow channel 21 that faces the air inflow direction. For the sound absorbing material 60, closed-cell foamed polyurethane or the like can be used.

  As described above, by providing the sound absorbing material 60 on the facing surface 23, the sound wave SW due to the self-excited vibration of the separation vortex SV generated in the diffuser portion 22 can be absorbed and attenuated by the sound absorbing material 60. Thereby, the noise of the resonance mode by the standing wave of the specific frequency area | region of 500 Hz vicinity can be suppressed. Therefore, it is possible to reduce noise caused by the separation flow generated in the diffuser portion 22 of the unit case 11.

  The present invention is not limited to the invention according to the above-described embodiment, and can be appropriately modified without departing from the gist thereof. For example, in the above-described embodiment, the air conditioner 1 for a vehicle that regulates the temperature by circulating the air blown from the left and right direction of the vehicle by the air blowing unit 2 in the front-rear direction by the air conditioning unit 3 has been described as an example. The same applies to a vehicle air conditioner for controlling the temperature by circulating air in the vertical direction, or for a vehicle air conditioner for controlling the temperature by circulating the air blown in the vertical direction by the air blowing unit in the longitudinal direction. Of course, it can be applied.

  Moreover, although the example in the case where the diffuser portion 22 has the enlarged portions on both the upper and lower sides has been described, the diffuser portion 22 may have an enlarged portion only on one side. Furthermore, a plurality of the inventions according to the above embodiments may be used in combination.

1 is an external perspective view of a vehicle air conditioner according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the air conditioning unit for the vehicle shown in FIG. 1 and the vicinity of an evaporator inlet channel of the air conditioning unit. FIG. 3 is a longitudinal sectional view taken along the core surface of the evaporator when FIG. 2 is viewed from above in the drawing. It is a partial longitudinal cross-sectional view of the concrete modification (A) thru | or (F) of the site | part corresponded in FIG. 3 of the vehicle air conditioner concerning 2nd Embodiment of this invention. Cross-sectional view (A) in the vicinity of the evaporator inlet flow path of the air-conditioning unit and the air-conditioning unit for the vehicle air conditioner according to the third embodiment of the present invention, and the vertical cross-sectional views (B) and (C) along the core surface of the evaporator ). It is a cross-sectional view near the evaporator inlet flow path of the air blowing unit and the air conditioning unit of the vehicle air conditioner according to the reference example of the present invention. It is a cross-sectional view near the evaporator inlet flow path of the air blowing unit and the air conditioning unit of the vehicle air conditioner according to the second reference example of the present invention. It is a graph which shows the relationship between the pressure (dimensionalless) and frequency (Hz) in embodiment shown in FIG. It is a graph which shows the relationship between the pressure (dimensionalless) and frequency (Hz) in embodiment shown to FIG. 4 (A). It is a model figure of the noise generation mechanism by the self-excited vibration of a separation vortex.

DESCRIPTION OF SYMBOLS 1 Vehicle air conditioner 2 Blower unit 3 Air conditioning unit 11 Unit case 13 Evaporator 13A Evaporator core surface 21 Evaporator inlet flow path 22 Diffuser part 23 The surface (facing surface) which opposes an air inflow direction
24 Reflection direction changing unit 25 Wedge-like uneven surface body 26 Curved curved surface body 27 Inclined surface body 28 Curved projecting surface 29 Inclined projecting surface 30, 31 Inclined surface 41 Stepped surface 42 Step surface SV Separation vortex SW Sound wave L Opposing separation vortex generation location Distance to face

Claims (6)

A blower unit that sucks outside air or inside air and blows it downstream; an air conditioning unit that regulates the temperature of the air blown from the blower unit and blows it into the passenger compartment;
The air conditioning unit is a vehicle air conditioner provided with a unit case that guides the air blown from the blower unit to an evaporator inlet flow path through a diffuser section and distributes the air from the evaporator inlet flow path to the evaporator.
Reflection direction change that changes the reflection direction of the sound wave by the self-excited vibration of the separation vortex generated in the diffuser part facing the diffuser part on the surface of the unit case that forms the evaporator inlet flow channel that faces the air inflow direction The vehicle air conditioner is characterized in that a portion is constituted by the facing surface itself of the unit case .   The vehicle air conditioner according to claim 1, wherein the sound wave reflection direction changing unit is configured by a wedge-shaped uneven surface.   The vehicle air conditioner according to claim 1, wherein the sound wave reflection direction changing unit is configured by a curved curved surface.   The vehicle air conditioner according to claim 1, wherein the sound wave reflection direction changing unit is configured by an inclined surface that is inclined with respect to a surface orthogonal to the air inflow direction. The surface facing the evaporator core surface in the unit case forming the evaporator inlet channel is a step-shaped surface along the air inflow direction,
On the step surface of the stepped surface facing the air inflow direction, there is provided a reflection direction changing unit that changes the reflection direction of the sound wave by the self-excited vibration of the separation vortex generated in the diffuser unit facing the diffuser unit. The vehicle air conditioner according to any one of claims 1 to 4.   6. The vehicle air conditioner according to claim 5, wherein the stepped surface is provided with a plurality of steps along the air inflow direction, and the reflection direction changing portion is provided on each step surface. apparatus.

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