Vehicle air conditioning blower

Abstract

To reduce noise caused during operation without adding limitations on a parting position of a case while avoiding increase in the number of components.SOLUTION: A centrifugal fan 10 is provided with: multiple main blades 11; a blade support plate part 12 which supports the main blades 11; and multiple sub-blades 13 protruding from the blade support plate part 12 to the motor flange 33 side. A clearance between an outer end part 13b of the sub-blade 13 and a tongue part 30d is set so as to be longer than a clearance between an outer end part 11b of the main blade 11 and the tongue part 30d.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a blower for a vehicle air conditioner mounted on, for example, an automobile, and particularly belongs to the technical field of a structure incorporating a centrifugal fan.

Background Art

[0002] As a blower for a vehicle air conditioner, there is known one including a centrifugal fan driven by a motor and a case for housing the centrifugal fan (see, for example, Patent Documents 1 to 6). The centrifugal fan is arranged such that its rotation axis extends in the vertical direction, and a motor is arranged below the centrifugal fan. The motor is attached to a motor flange that constitutes the bottom wall portion of the case. When the centrifugal fan rotates by the motor, air is sucked from above the centrifugal fan and then blown out from between the blades of the centrifugal fan into the air blowing passage in the case, and the air blown out into the air blowing passage forms air-conditioning air that is sent to each part of the passenger compartment.

[0003] In a blower using a centrifugal fan, if the gap formed between the bottom surface of the centrifugal fan and the upper surface of the motor flange is large, an air flow from the air blowing passage toward the gap is likely to occur. As a result, the air flow in the air blowing passage is disturbed, which may cause noise and performance degradation. Therefore, it is preferable that the gap be small. However, since the rotation axis of the motor during rotation vibrates, it is necessary to secure a certain amount of gap from the viewpoint of avoiding collision between the fan and the motor flange due to the vibration or motor lock caused by foreign matter being pinched into the gap between the fan and the motor.

[0004] In Patent Documents 1 and 2, cylindrical ribs having different diameters are provided on the lower surface of the fan and the upper surface of the motor flange, respectively, to suppress the air flow toward the gap. Further, in Patent Document 3, a step is provided at the start portion of the winding of the air blowing passage in the case, and a protrusion is provided at the end portion of the winding to suppress the air flow toward the gap.

[0005] Furthermore, Patent Documents 4 to 6 disclose structures to counter the noise generated when periodic pressure fluctuations caused by the rotation of a centrifugal fan are converted into sound. In Patent Document 4, a separate tongue is provided on the case, with a notch formed in part of it, while in Patent Document 5, a stepped portion is formed in the tongue, and in Patent Document 6, the radial distance between the tongue and the blade on the suction side is set to be smaller than on the anti-suction side. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 4185654 [Patent Document 2] Patent No. 6111914 [Patent Document 3] Patent No. 5775515 [Patent Document 4] Japanese Patent Application Publication No. 5-65897 [Patent Document 5] Japanese Utility Model Application Publication No. 7-14192 [Patent Document 6] Patent No. 4026366 Summary of the Invention [Problem to be solved by the invention]

[0007] However, when cylindrical ribs or protrusions are provided to suppress the flow of air from the air passage toward the gap as in Patent Documents 1 to 3, the noise reduction effect is low unless the gap is made as small as possible, so the vertical dimension of the cylindrical ribs or protrusions needs to be large, but this makes it more likely that the fan will collide with the cylindrical ribs / protrusions, making it difficult to ensure the desired gap, and as a result, there is a risk of the noise reduction effect being reduced.In addition, a small gap raises the concern that the motor may lock due to foreign matter getting caught.

[0008] On the other hand, it is conceivable to provide a sub-blade different from the main blade on the lower surface of the fan to generate an air flow that prevents the air in the air supply passage from flowing toward the gap. This avoids motor lock due to foreign matter being pinched, but the relatively short radial distance between the sub-blade and the tongue portion adds NZ noise generated by the sub-blade, which may increase the noise of the blower.

[0009] In order not to increase the NZ noise, it is conceivable to apply the structures of Patent Documents 4 to 6, but the following problems occur. That is, in Patent Document 4, it is necessary to separately manufacture the tongue portion, and the increase in the number of parts leads to an increase in material costs and assembly costs, which is a problem. In Patent Document 5, when trying to provide a stepped difference, the mold parting position of the case is restricted, and the degree of freedom in layout is reduced. Furthermore, in Patent Document 6, when trying to make the radial distance between the tongue portion on the suction side and the blade smaller than that on the anti-suction side, the mold parting position of the case is restricted, so the degree of freedom in layout is reduced.

[0010] The present invention has been made in view of such points, and an object thereof is to avoid an increase in the number of parts and to reduce the noise during operation without restricting the mold parting position of the case.

Means for Solving the Problems

[0011] To achieve the above object, a first aspect of the present disclosure can be based on a vehicle air-conditioning blower including a centrifugal fan, a motor that rotationally drives the centrifugal fan, and a case that houses the centrifugal fan and forms an air passage around the centrifugal fan. A bellmouth is provided on the suction side of the case of the centrifugal fan, and a motor flange, to which the motor is attached, is provided on the side of the case opposite the suction side of the centrifugal fan. A tongue portion is also provided at a spiral start portion of the case. The centrifugal fan includes a plurality of main blades that extend elongated in the direction of a rotation axis of the motor and are spaced apart from one another in the circumferential direction, and a plurality of sub-blades that are spaced apart from one another in the circumferential direction on the motor flange side of the main blades, and the distance between outer ends of the sub-blades and the tongue portion is set to be longer in the radial direction of the rotation axis than the distance between outer ends of the main blades and the tongue portion.

[0012] With this configuration, when the centrifugal fan rotates due to the rotation of the motor, air is drawn into the centrifugal fan through the bellmouth and then flows out between the main blades into the air passage of the case. As the centrifugal fan rotates, the secondary blades rotate on the motor flange side. By utilizing the air flow generated by these secondary blades, air that has once flowed out between the main blades into the air passage is less likely to flow back into the gap between the centrifugal fan and the motor flange. This reduces noise caused by backflow of air even if the gap is somewhat large, thereby preventing motor lock due to the entrapment of foreign objects.

[0013] In addition, by providing the auxiliary blades, there is a concern that the periodic pressure fluctuations caused by the rotation of the auxiliary blades are converted into sound, resulting in the generation of NZ sound. However, since the separation distance between the outer end portion of the auxiliary blade and the tongue portion is long, the wind speed when the air flowing out between the auxiliary blades collides with the tongue portion decreases. As a result, a separate tongue portion as in Patent Document 4 becomes unnecessary, and an increase in the number of parts is avoided. Moreover, without providing a configuration such as the stepped step in Patent Document 5 or making the radial distance between the tongue portion on the suction side and the blade smaller on the anti-suction side than on the suction side, the NZ sound caused by providing the auxiliary blades is reduced.

[0014] In the second aspect of the present disclosure, the number of the main blades is different from the number of the auxiliary blades.

[0015] That is, in the NZ sound, the sound pressure increases at the frequency of the number of blades × the rotational speed of the centrifugal fan and its integral multiples. Therefore, when the number of blades is changed, the frequency in the region where the sound pressure of the NZ sound is high changes. Accordingly, in this configuration, since the number of the main blades is different from the number of the auxiliary blades, the frequency at which the sound pressure increases due to the rotation of the main blades and the frequency at which the sound pressure increases due to the rotation of the auxiliary blades can be shifted, and the amplification of the NZ sound is suppressed.

[0016] In the third aspect of the present disclosure, the number of the main blades is set to be larger than the number of the auxiliary blades.

[0017] That is, by making the number of the auxiliary blades smaller than that of the main blades, the air volume blown by the auxiliary blades can be made smaller than the air volume blown by the main blades.

[0018] In the fourth aspect of the present disclosure, the centrifugal fan is provided with a blade support plate portion that supports the end portion of the main blade on the motor flange side, and the auxiliary blade protrudes from the blade support plate portion toward the motor flange side.

[0019] According to this configuration, both the main blade and the sub-blade can be provided on a single blade support plate portion.

[0020] In a fifth aspect of the present disclosure, the motor flange is provided with an annular wall portion that protrudes toward the centrifugal fan side and extends annularly so as to surround the motor, and the annular wall portion is closer to the blade support plate portion than the tip end portion in the protruding direction of the sub-blade, and a gap of a predetermined size or more is provided between the outer peripheral surface of the annular wall portion and the sub-blade.

[0021] According to this configuration, for example, the motor cooling air flowing out from the motor flows from the inside to the outside of the annular wall portion and easily flows into the space between the sub-blades, so the cooling efficiency of the motor is improved.

[0022] In a sixth aspect of the present disclosure, the distance in the rotational axis direction between the tip end portion in the protruding direction of the sub-blade and the portion of the motor flange facing the tip end portion in the protruding direction of the sub-blade is set to 5.0 mm or more.

[0023] According to this configuration, the tip end portion of the sub-blade in the protruding direction does not collide with the motor flange during operation. Further, it is possible to prevent the sandwiching of foreign matter that has entered between the sub-blade and the motor flange and the locking of the centrifugal fan due to the freezing of water that has entered between the sub-blade and the motor flange.

[0024] In a seventh aspect of the present disclosure, the centrifugal fan is an integrally molded product made of a resin material, and gate traces are provided on the sub-blades that are circumferentially separated from each other among the plurality of sub-blades, and the sub-blades provided with the gate traces are arranged at equal intervals in the circumferential direction.

[0025] That is, the fact that the sub-blades provided with the gate traces are arranged at equal intervals in the circumferential direction means that when molding the centrifugal fan, the molten resin can be injected at equal intervals at a plurality of locations in the cavity of the mold, so the molten resin easily flows evenly in the cavity, and molding defects are less likely to occur.

[0026] In an eighth aspect of the present disclosure, the radial dimension of the rotation axis in the auxiliary blade is set shorter than the radial dimension of the rotation axis in the main blade.

[0027] That is, by relatively shortening the radial dimension of the auxiliary blade, the air volume blown by the auxiliary blade can be made smaller than the air volume blown by the main blade.

[0028] In a ninth aspect of the present disclosure, in the radial direction of the rotation axis, the separation distance between the center line of the centrifugal fan and the inner end of the auxiliary blade is set longer than the separation distance between the center line of the centrifugal fan and the inner end of the main blade.

[0029] That is, since the inner end of the auxiliary blade can be separated from the motor, the motor cooling air flowing out from the motor can flow more easily, and the cooling efficiency of the motor is further improved.

Advantages of the Invention

[0030] As described above, since the centrifugal fan is provided with the main blade and the auxiliary blade, and the separation distance between the outer end of the auxiliary blade and the tongue is set longer than the separation distance between the outer end of the main blade and the tongue, an increase in the number of parts is avoided, and the noise during operation can be reduced without imposing restrictions on the mold parting position of the case.

Brief Description of the Drawings

[0031]

Figure 1

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Embodiments for Carrying Out the Invention

[0032] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. It should be noted that the following description of the preferred embodiments is merely illustrative in nature and is not intended to limit the present invention, its applications, or its uses.

[0033] FIG. 1 shows a blower 1 for a vehicle air conditioner according to an embodiment of the present invention. The blower 1 for a vehicle air conditioner is for sending air to a vehicle air conditioner (not shown) mounted on, for example, an automobile or the like. The vehicle air conditioner includes, for example, an indoor unit including a cooling heat exchanger composed of an evaporator or the like, a heating heat exchanger composed of a heater core or the like, an electric heater, etc., and an outdoor unit including a compressor, a condenser, etc. The indoor unit includes an air-conditioning casing that houses the cooling heat exchanger and the heating heat exchanger. The air-conditioning casing is configured to introduce the air sent from the blower 1 for a vehicle air conditioner. Inside the air-conditioning casing, a temperature adjustment damper, a blow direction switching damper for switching the blow direction of the conditioned air, etc. are built in, and after the air introduced into the air-conditioning casing is temperature-adjusted by the cooling heat exchanger and the heating heat exchanger, it can be supplied into the vehicle interior from a desired air outlet. The configurations of the indoor unit and the outdoor unit are well known in the art.

[0034] The indoor unit is housed inside an instrument panel (not shown) disposed at the front end portion of the vehicle interior. The blower 1 for a vehicle air conditioner is also housed inside the instrument panel, and for example, the indoor unit and the blower 1 for a vehicle air conditioner can be arranged side by side in the vehicle width direction. In this state, the blower 1 for a vehicle air conditioner is connected to the indoor unit, and the entire amount of the air sent from the blower 1 for a vehicle air conditioner can be introduced into the indoor unit. Note that the blower 1 for a vehicle air conditioner may be integrated with the indoor unit or the two may be separate. Further, the blower 1 for a vehicle air conditioner may be a device that constitutes a part of the vehicle air conditioner.

[0035] (Overall configuration of the blower 1 for a vehicle air conditioner) As shown in FIGS. 1 to 4, the blower 1 for a vehicle air conditioner includes a centrifugal fan 10, a motor 20 that rotationally drives the centrifugal fan 10, and a case 30 that houses the centrifugal fan 10 and forms a blower passage S1 around the centrifugal fan 10. In this embodiment, the centrifugal fan 10 is disposed in a posture in which the rotation center line E (shown in FIG. 4) of the centrifugal fan 10 extends in the vertical direction. In the description of this embodiment, the case where the rotation center line E extends in the vertical direction will be described, but the rotation center line E may be inclined or may extend in the horizontal direction.

[0036] When the centrifugal fan 10 rotates, it is configured to suck air from above the centrifugal fan 10 and then blow out the sucked air in the radial direction (horizontal direction) of the centrifugal fan 10. Therefore, the motor 20 is disposed below the centrifugal fan 10 and is laid out so as not to obstruct the suction of air from above.

[0037] The upper part of the case 30 serves as the suction side, and an inside / outside air switching section (not shown) is provided in the upper part of the case 30. The inside / outside air switching section has an inside air intake port for taking in air inside the vehicle compartment, an outside air intake port for taking in air outside the vehicle compartment, and an inside / outside air switching damper for opening and closing the inside air intake port and the outside air intake port. By operating the inside / outside air switching damper, it is possible to switch between an inside air circulation mode in which only the inside air intake port is opened and an outside air introduction mode in which only the outside air intake port is opened.

[0038] (Configuration of the motor 20) As shown in FIG. 4, the motor 20 includes a motor main body 21 that incorporates a rotor and a stator (not shown), and a rotating shaft 22. The motor main body 21 is attached to a motor flange 33, details of which will be described later. Although not shown, a wiring for supplying power is connected to the motor main body 21. When the vehicle air conditioner is in operation, power is supplied to the motor main body 21 via the wiring. By adjusting the voltage applied to the motor main body 21, the number of rotations per unit time of the rotating shaft 22 can be changed.

[0039] The rotating shaft 22 extends in the vertical direction and protrudes upward from the central part of the motor main body 21. Further, the upper surface of the motor main body 21 is inclined or curved so as to be positioned lower as it approaches the radially outer end portion.

[0040] Cooling air is introduced into the motor main body 21. Specifically, an inlet (not shown) for cooling air is formed on the lower surface of the motor main body 21, while an outlet (not shown) for cooling air is formed in a portion near the center of the upper surface of the motor main body 21. The cooling air that has flowed through the cooling air passage S2 described later is introduced into the interior of the motor main body 21 from the inlet and then led out from the outlet, and the motor main body 21 is cooled by this flow of cooling air. Note that the positions and numbers of the inlet and the outlet can be arbitrarily set.

[0041] (Configuration of the centrifugal fan 10) As shown in FIGS. 7 to 13, the centrifugal fan 10 is a sirocco fan. That is, as shown in FIG. 9, the centrifugal fan 10 is provided with a plurality of main blades 11, a blade support plate portion 12, a plurality of sub - blades 13, a cone - shaped portion 16, and a cylindrical portion 17. The main blades 11, the blade support plate portion 12, the sub - blades 13, the cone - shaped portion 16, and the cylindrical portion 17 are integrally formed of a resin material. Therefore, the centrifugal fan 10 is an integrally - formed product. When molding the centrifugal fan 10, for example, an injection molding method can be used. The centrifugal fan 10 is made of a resin material having a strength equal to or higher than a predetermined value so that it does not undergo large deformation even when the centrifugal fan 10 is rotating at its maximum rotational speed.

[0042] As shown in FIG. 4, the cylindrical portion 17 is concentric with the rotation center line E of the centrifugal fan 10 and extends in the vertical direction. The upper part of the rotating shaft 22 of the motor 20 is inserted into the cylindrical portion 17 and coupled thereto. In this embodiment, as shown in FIG. 7, a collar A is press-fitted between the cylindrical portion 17 and the upper part of the rotating shaft 22, and the cylindrical portion 17 and the upper part of the rotating shaft 22 are coupled in a non-rotating state via this collar A so as not to rotate relative to each other. The coupling structure between the cylindrical portion 17 and the rotating shaft 22 is not limited to the above-described structure, and for example, a fastening structure using nuts, fasteners, or the like may be used.

[0043] As shown in FIG. 4, the conical portion 16 has a plate shape extending radially from the outer peripheral surface of the middle portion in the vertical direction of the cylindrical portion 17, and is located between the side where the main blade 11 is provided and the side where the sub-blade 13 is provided, and partitions the main blade 11 side and the sub-blade 13 side. The motor body portion 21 is disposed below the conical portion 16, and the lower surface of the conical portion 16 and the motor body portion 21 face each other with a vertical gap therebetween. Since the cooling air outlet of the motor body portion 21 opens on the upper surface of the motor body portion 21, the cooling air discharged from the motor body portion 21 flows between the lower surface of the conical portion 16 and the upper surface of the motor body portion 21. The cooling air discharged from the motor body portion 21 flows radially outward between the lower surface of the conical portion 16 and the upper surface of the motor body portion 21 and flows into the air supply passage S1. That is, a cooling air discharge passage S3 for discharging the cooling air is formed between the lower surface of the conical portion 16 and the upper surface of the motor body portion 21, and the downstream end of this cooling air discharge passage S3 communicates with the air supply passage S1.

[0044] The conical portion 16 is inclined or curved such that it is positioned lower as it approaches the radially outer end thereof. The radial center of the conical portion 16 is located on the axis of the cylindrical portion 17. The shape of this conical portion 16 corresponds to the shape of the upper surface of the motor main body portion 21. The height of the radially outer end of the conical portion 16 is lower than the lower end of the cylindrical portion 17 and is substantially the same height as the radially outer end of the upper surface of the motor main body portion 21. The radially outer end of the conical portion 16 extends radially outward beyond the radially outer end of the upper surface of the motor main body portion 21. Therefore, the outer diameter of the conical portion 16 is larger than the outer diameter of the upper surface of the motor main body portion 21.

[0045] The blade support plate portion 12 extends radially outward from the radially outer end of the conical portion 16 and extends continuously in the circumferential direction. Therefore, the blade support plate portion 12 forms an annular shape that extends substantially horizontally. The radial center of the blade support plate portion 12 is located on the axis of the cylindrical portion 17.

[0046] As shown in FIG. 11, the plurality of main blades 11 are for forming an air flow sent to the air conditioner unit, extend long in the direction of the rotation shaft 22 of the motor 20, and are arranged at intervals in the circumferential direction. As shown in FIG. 10, the circumferential intervals of the main blades 11 are equal. When the centrifugal fan 10 rotates, the air sucked from above blows out radially outward from between the circumferentially adjacent main blades 11 and flows into the air supply passage S1 shown in FIG. 4. The lower end portion (the end portion on the motor flange 33 side) of each main blade 11 is supported by the blade support plate portion 12. Specifically, the lower end portion of each main blade 11 is integrally formed on the upper surface of the blade support plate portion 12, and each main blade 11 extends upward from the upper surface of the blade support plate portion 12. Each main blade 11 has a curved wing shape. In this embodiment, since there are a large number of main blades 11, the centrifugal fan 10 can also be called a centrifugal multi-blade fan.

[0047] As shown in FIG. 9, the centrifugal fan 10 has an upper connecting portion 14 that connects the upper ends of the main blades 11. The upper connecting portion 14 is integrally formed with the upper ends of the main blades 11, protrudes upward from the upper ends of the main blades 11, and is formed in an annular shape. Further, the centrifugal fan 10 has an intermediate connecting portion 15 that connects the intermediate portions in the vertical direction of the main blades 11. The intermediate connecting portion 15 is integrally formed with the outer end portion in the direction of the rotation axis 22 of the main blade 11, and is formed in an annular shape similarly to the upper connecting portion 14.

[0048] The plurality of sub-blades 13 are for suppressing the air in the air supply passage S1 from flowing into the cooling air discharge passage S3. When the centrifugal fan 10 rotates, the plurality of sub-blades 13 rotate below the blade support plate portion 12, thereby forming an air flow toward the outer side in the radial direction. This air flow is weaker than the air flow formed by the rotation of the main blade 11.

[0049] Each sub-blade 13 protrudes downward (toward the motor flange 33 side) from the lower surface of the blade support plate portion 12 and is arranged at intervals in the circumferential direction. The circumferential intervals of the sub-blades 13 are equal. The vertical length of the sub-blade 13 is set shorter than the vertical length of the main blade 11, and the vertical length of the sub-blade 13 can be set to 1 / 4 or less of the vertical length of the main blade 11. This is because it is sufficient for the sub-blade 13 to form a relatively weak flow that suppresses the inflow of air into the cooling air discharge passage S3. Each sub-blade 13 is also formed in a curved wing shape similar to the main blade 11. Specifically, the vertical length of the main blade 11 can be set in the range of, for example, 50 mm or more and 100 mm or less, and the vertical length of the sub-blade 13 can be set in the range of 5 mm or more and 30 mm or less.

[0050] As shown in Fig. 12, the number of main blades 11 is different from the number of sub - blades 13. The reason is to change the frequency range where the sound pressure of the NZ sound generated by the rotation of the main blade 11 is high and the frequency range where the sound pressure of the NZ sound generated by the rotation of the sub - blade 13 is high. In Fig. 12, the centrifugal fan 10 is viewed from below. Therefore, the sub - blade 13 is shown by a solid line and the main blade 11 is shown by a dashed line. In this embodiment, the number of main blades 11 is set to be more than the number of sub - blades 13. Specifically, the number of main blades 11 is 41 and the number of sub - blades 13 is 40. The reason for reducing the number of sub - blades 13 is that the sub - blade 13 only needs to form a relatively weak flow that suppresses the inflow of air into the cooling air discharge passage S3. Note that the number of main blades 11 and the number of sub - blades 13 can be set arbitrarily, and the difference in the number only needs to be 1 or more. It is also possible to set the difference in the number to 2, 3, or 4. Also, the number of main blades 11 may be less than the number of sub - blades 13.

[0051] When the centrifugal fan 10 is viewed in the direction of the rotation center line E (the vertical direction in this example), since the number of main blades 11 is different from the number of sub - blades 13, some of the main blades 11 and some of the sub - blades 13 are in a positional relationship of overlapping each other in the vertical direction, while the other main blades 11 and the other sub - blades 13 are in a positional relationship of not overlapping each other in the vertical direction. In Fig. 12, some of the main blades 11 and sub - blades 13 located on the right side overlap in the vertical direction, but the main blades 11 and sub - blades 13 located on the upper side, lower side, and right side do not overlap in the vertical direction.

[0052] As shown in Fig. 5, the radial dimension W2 of the rotation axis 22 in the auxiliary blade 13 is set shorter than the radial dimension W1 of the rotation axis 22 in the main blade 11. The dimension W2 is the dimension from the radially inner end portion 13a to the outer end portion 13b of the rotation axis 22 of the auxiliary blade 13, and can also be said to be the dimension in the width direction of the auxiliary blade 13. Further, the dimension W1 is the dimension from the radially inner end portion 11a to the outer end portion 11b of the rotation axis 22 of the main blade 11, and can also be said to be the dimension in the width direction of the main blade 11. In this embodiment, the ratio of the dimension W2 to the dimension W1 is set in the range of, for example, 1 / 2 to 3 / 4.

[0053] Also, regarding the radial direction of the rotation axis 22, the separation distance between the rotation center line E of the centrifugal fan 10 and the inner end portion 13a (the above-mentioned radially inner end portion) of the auxiliary blade 13 is set longer than the separation distance between the rotation center line E and the inner end portion 11a (the above-mentioned radially inner end portion) of the main blade 11. In other words, the inner end portion 11a of the main blade 11 is closer to the rotation center line E than the inner end portion 13a of the auxiliary blade 13. Further, the outer end portion 11b of the main blade 11 is farther from the rotation center line E than the outer end portion 13b of the auxiliary blade 13.

[0054] Fig. 13 is a bottom view of the centrifugal fan 10. This figure shows the gate trace 13a formed when the centrifugal fan 10 is injection-molded. Among the plurality of auxiliary blades 13, a gate trace 13a is provided on a specific auxiliary blade 13A that is circumferentially separated from each other, and the specific auxiliary blade 13a provided with the gate trace 13a is arranged at equal intervals in the circumferential direction. In this embodiment, there are four specific auxiliary blades 13A, and therefore the four specific auxiliary blades 13A are provided at intervals of 90°. Incidentally, the specific auxiliary blade 13A can be provided in any number of two or more. For example, if there are three, they may be provided at intervals of 120°, and if there are six, they may be provided at intervals of 60°.

[0055] As shown in the partial enlarged view of FIG. 13, the gate trace 13a is provided in the middle portion in the width direction of the sub-blade 13A. When the thickness dimension of the portion of the sub-blade 13A where the gate trace 13a is not provided is T1, and the thickness dimension of the portion of the sub-blade 13A where the gate trace 13a is provided is T2, the dimension T2 is longer than the dimension T1. That is, the thickness of the portion where the gate trace 13a is provided is thicker than other portions.

[0056] When injection molding a resin molded product such as the centrifugal fan 10, although not shown, an injection cylinder that kneads and melts the resin and then injects it at a predetermined pressure, and a mold configured to be separable are used. The molten resin injected from the injection cylinder is filled into the cavity in the mold in the mold-clamped state. At this time, as in this embodiment, the fact that the sub-blades 13A provided with the gate traces 13a are arranged at equal intervals in the circumferential direction means that when molding the centrifugal fan 10, the molten resin can be injected at equal intervals in the circumferential direction at a plurality of locations in the cavity of the mold. Thereby, the molten resin easily flows evenly in the cavity, and molding defects are less likely to occur. In addition, gates other than the above may be set as appropriate.

[0057] Further, a plurality of ribs 18 are formed radially on the lower surface of the cone-shaped portion 16. The inner end portions of the respective ribs 18 are connected to the outer peripheral surface of the cylindrical portion 17, and the cylindrical portion 17 and the cone-shaped portion 16 are connected by the ribs 18. The ribs 18 may be omitted.

[0058] (Configuration of the case 30) As shown in FIGS. 1 and 2, the case 30 includes an upper split case 31, a lower split case 32, and a motor flange 33. The upper split case 31, the lower split case 32, and the motor flange 33 are made of, for example, a highly rigid resin material. As shown in FIG. 4, the upper split case 31 is a portion that constitutes the upper end portion of the case 30 from the middle portion in the vertical direction to the upper end portion, and is open downward. The lower split case 32 is a portion that constitutes the bottom portion of the case 30 from the middle portion in the vertical direction to the bottom portion, and is open upward. By fitting the lower end portion of the upper split case 31 and the upper end portion of the lower split case 32, an air supply passage S1 is partitioned and formed inside. The scroll casing is constituted by the upper split case 31 and the lower split case 32.

[0059] The upper side of the upper split case 31 is the suction side of the centrifugal fan 10 in the case 30. On the upper wall portion of the upper split case 31, a bellmouth portion 31a that opens in a circular shape and is curved downward is formed so as to penetrate the upper wall portion in the vertical direction. The opening center of the bellmouth portion 31a is located concentrically with the rotation center line E of the centrifugal fan 10. As shown in FIG. 4, the lower end portion of the bellmouth portion 31a extends below the upper end portion of the centrifugal fan 10 and is located inside the upper end connecting portion 14. The bellmouth portion 31a is connected to the inside / outside air switching portion.

[0060] As shown in Fig. 6, the air supply passage S1 extends in a scroll shape surrounding the periphery of the centrifugal fan 10. The air blown out from the centrifugal fan 10 converges in the air supply passage S1 and flows downstream. A tongue portion 30d is provided at the starting portion (starting point) S1a of the air supply passage S1 on the inner wall surface of the case 30. The tongue portion 30d is a portion that diverts the air flow into the main flow direction (the direction in which the downstream portion S1b of the air supply passage S1 extends) and the scroll winding direction, and is closest to the main blade 11 of the centrifugal fan 10 on the inner peripheral surface of the case 30. That is, a curved surface portion protruding into the air supply passage S1 is formed on the inner wall surface of the starting portion S1a of the air supply passage S1, and the tongue portion 30d is constituted by this curved surface portion. The curved surface portion constituting the tongue portion 30d is constituted by, for example, an arc surface that extends in an arc shape when viewed in a horizontal cross section.

[0061] The cross section in the direction orthogonal to the air flow direction of the air supply passage S1 is the narrowest at the tongue portion 30d and expands as it approaches the downstream end. The expansion direction of the cross section of the air supply passage S1 is both in the vertical direction and the radial direction, but it may expand only in the radial direction. The downstream portion S1b of the air supply passage S1 extends linearly. As shown in Fig. 1 and the like, the downstream end of the air supply passage S1 opens on the outer surface of the case 30, and this opening is the air outlet 30a. The air outlet 30a is connected to the air conditioning casing of the indoor unit.

[0062] As shown in Fig. 5, the tongue portion 30d is continuously formed from the portion facing the outer end portion 11b of the main blade 11 of the centrifugal fan 10 to the portion facing the outer end portion 13b of the auxiliary blade 13. The shape of the tongue portion 30d is substantially the same from the upper end portion to the lower end portion, while the outer end portion 13b of the auxiliary blade 13 is located radially inward of the outer end portion 11b of the main blade 11. Therefore, in the radial direction of the rotation axis 22, the separation distance D2 between the outer end portion 13b of the auxiliary blade 13 and the tongue portion 30d is set longer than the separation distance D1 between the outer end portion 11b of the main blade 11 and the tongue portion 30d.

[0063] As shown in FIGS. 1 and 3, an upper bulging portion 30c bulging outward is formed in the vicinity of the tongue portion 30d in the upper divided case 31 and the lower divided case 32. Inside the upper bulging portion 30c, an upper portion of the cooling air passage S2 is formed to extend in the vertical direction. As shown in FIG. 6, a cooling air inlet 30e is formed on the inner surface of the upper divided case 31 on the downstream side of the tongue portion 30d. This cooling air inlet 30e communicates with the upstream end of the cooling air passage S2.

[0064] Also, the lower side of the lower divided case 32 is on the side opposite to the suction side of the centrifugal fan 10 in the case 30. As shown in FIG. 4, a circular opening 32a is formed in the bottom of the lower divided case 32 so as to penetrate the bottom of the lower divided case 32 in the vertical direction. The center of the opening 32a is located concentrically with the rotation center line E of the centrifugal fan 10. The diameter of the opening 32a is set to be larger than the opening diameter of the bellows portion 31a and also larger than the diameter of the maximum outer diameter portion of the centrifugal fan 10. Therefore, when manufacturing the blower 1 for the vehicle air conditioner, for example, the centrifugal fan 10 can be accommodated from below the case 30.

[0065] A motor flange 33 to which the motor 20 is attached is provided at the bottom of the lower divided case 32. The motor flange 33 includes an annular plate portion 33a extending in the radial direction of the centrifugal fan 10, a motor housing portion 33b, and a lower bulging portion 33c. The outer diameter of the annular plate portion 33a is set to be larger than the opening 32a of the lower divided case 32, and the opening 32a is closed by the annular plate portion 33a. Also, a plurality of portions of the annular plate portion 33a are detachably fixed to the bottom of the lower divided case 32.

[0066] The motor housing portion 33b is formed to be recessed downward. The lower portion of the motor main body portion 21 is housed inside this motor housing portion 33b. The motor main body portion 21 is fixed to the annular plate portion 33a and the motor housing portion 33b, and relative rotation is impossible. The lower bulging portion 33c is positioned corresponding to the upper bulging portion 30c. Inside this lower bulging portion 33c, the lower portion of the cooling air passage S2 is formed. The downstream end of the cooling air passage S2 is connected to the inlet of the cooling air of the motor main body portion 21.

[0067] On the upper surface of the annular plate portion 33a of the motor flange 33, an annular wall portion 33d is provided which protrudes toward the centrifugal fan 10 side (upper side) and extends annularly so as to surround the motor 20. Above the annular wall portion 33a exactly, the cone-shaped portion 16 is positioned. The center of the annular wall portion 33d is positioned concentrically with the rotation center line E of the centrifugal fan 10. The upper end portion of the annular wall portion 33d is positioned above the lower end portion of the sub-blade 13 (the tip portion in the protruding direction of the sub-blade 13). That is, the upper end portion of the annular wall portion 33d is provided so as to be closer to the blade support plate portion 12 than the lower end portion of the sub-blade 13.

[0068] And, a gap of a predetermined size or more is provided between the outer peripheral surface of the annular wall portion 33d and the sub-blade 13. That is, the outer diameter of the annular wall portion 33d is set smaller than the inner diameter of the blade support plate portion 12. As shown in FIG. 5, the separation distance D4 between the outer peripheral surface of the annular wall portion 33d and the inner end portion 13a of the sub-blade 13 is set to, for example, 5 mm or more. The upper limit of the separation distance D4 can be set to, for example, 15 mm or 10 mm.

[0069] The auxiliary blade 13 is disposed outside the annular wall portion 33d. The distance D3 in the direction of the rotation axis 22 between the lower end portion of the auxiliary blade 13 and the portion of the motor flange 33 facing the lower end portion of the auxiliary blade 13 is set to be 5.0 mm or more. The distance D3 can be set to, for example, 6.0 mm or more or 7.0 mm or more. The distance D3 and the separation distance D4 may be the same, or one may be longer than the other. The upper limit of the distance D3 can be, for example, 20 mm or 15 mm, thereby avoiding an increase in the size of the blower 1 for a vehicle air conditioner.

[0070] (During operation of the blower 1 for a vehicle air conditioner) When electric power is supplied to the motor 20 of the blower 1 for a vehicle air conditioner, the rotation shaft 22 rotates, and thereby the centrifugal fan 10 rotates. When the centrifugal fan 10 rotates, the air above the case 30 is taken into the case 30 from the bell mouth portion 31a. The air taken into the case 30 is sucked from above the centrifugal fan 10 inward of the centrifugal fan 10, flows along the upper surface of the cone-shaped portion 16, and then flows out radially outward between the main blades 11. The air flowing out between the main blades 11 flows into the air supply passage S1 and flows in a scroll shape starting from the tongue portion 30d, and then flows out of the case 30 from the air outlet 30a. At this time, since the outer end portion 11b of the main blade 11 is brought close to the tongue portion 30d and the separation distance D1 is made sufficiently short, the air supply efficiency is improved.

[0071] Further, when the centrifugal fan 10 rotates, the auxiliary blade 13 rotates between the blade support plate portion 12 and the upper surface of the annular plate portion 33a of the motor flange 33. By utilizing the air flow generated by the auxiliary blade 13, the air that has once flowed out from between the main blades 11 to the air supply passage S1 is less likely to flow backward into the gap between the centrifugal fan 10 and the upper surface of the annular plate portion 33a. Thereby, even if the gap between the centrifugal fan 10 and the upper surface of the annular plate portion 33a becomes somewhat larger, the noise caused by the backward flow of air is reduced. That is, while reducing the noise, the gap between the centrifugal fan 10 and the upper surface of the annular plate portion 33a can be increased to avoid motor lock due to the pinching of foreign matter.

[0072] Further, by providing the auxiliary blades 13, there is a concern that periodic pressure fluctuations caused by the rotation of the auxiliary blades 13 may be converted into sound, resulting in the generation of NZ sound. However, since the separation distance D2 between the outer end portion 13b of the auxiliary blade 13 and the tongue portion 30d is longer than the separation distance D1 between the main blade 11 and the tongue portion 30d, the wind speed when the air flowing out from between the auxiliary blades 13 collides with the tongue portion 30d decreases. As a result, a separate tongue portion as in Patent Document 4 becomes unnecessary, increasing the number of parts is avoided, and without providing a configuration such as the stepped step in Patent Document 5 or making the radial distance between the tongue portion on the suction side and the blade smaller than that on the anti-suction side in Patent Document 6, the NZ sound caused by providing the auxiliary blades 13 is reduced.

[0073] Also, in the NZ sound, the sound pressure increases at frequencies that are the number of each of the blades 11 and 13 of the centrifugal fan 10 × the rotation speed of the centrifugal fan 10 and integer multiples thereof. Therefore, for example, if the number of each of the blades 11 and 13 is the same, it has components that are prominent at the number of those blades × the rotation speed of the centrifugal fan 10 and integer multiples thereof. As a result, the overall noise level increases and it easily becomes a noise component that is annoying to the passengers. In the present embodiment, it utilizes the fact that the frequency of the region where the sound pressure of the NZ sound is high changes by changing the number of each of the blades 11 and 13. Specifically, by making the number of the main blades 11 different from the number of the auxiliary blades 13, the frequency at which the sound pressure increases due to the rotation of the main blades 11 and the frequency at which the sound pressure increases due to the rotation of the auxiliary blades 13 are shifted. As a result, the amplification of the NZ sound is suppressed.

[0074] The NZ sound is roughly classified into two types: the sound generated by the centrifugal fan 10 alone and the sound generated due to pressure fluctuations caused by the air flow colliding with the tongue portion 30d. The main cause of the NZ sound of the blower 1 for a vehicle air conditioner is the latter. In the present embodiment, since the latter NZ sound can be reduced, the effect of reducing noise is significant.

[0075] If the separation distance D2 between the outer end portion 13b of the auxiliary blade 13 and the tongue portion 30d is increased, the air recirculating in the air supply passage S1 increases, which may reduce the air supply efficiency. However, since the air discharged by the auxiliary blade 13 is not the main flow and has a small flow rate, increasing the separation distance D2 has little effect on the air supply efficiency.

[0076] In addition, by providing the auxiliary blade 13, it is possible to effectively increase the separation distance D2 from the tongue portion 30d only for the lower side where the NZ sound is particularly likely to occur, and the effect of reducing the NZ sound is significant. With only the main blade 11, it is difficult in terms of die structure to change the shape only on the lower side of the blade 11 to change the separation distance from the tongue portion 30d.

[0077] Further, when the centrifugal fan 10 rotates, the static pressure in the air supply passage S1 increases, so the air in the air supply passage S1 flows into the cooling air passage S2 from the cooling air intake 30e. The air that has flowed into the cooling air passage S2 flows downward and flows into the motor main body 21 from the cooling air inlet of the motor main body 21, and then flows out from the upper surface of the motor main body 21 to the cooling air discharge passage S3. At this time, since the separation distance D4 between the outer peripheral surface of the annular wall portion 33d and the inner end portion 13a of the auxiliary blade 13 is set to 5 mm or more, the cooling air flowing out from the motor main body 21 easily flows from the inside to the outside of the annular wall portion 33d and flows into the space between the auxiliary blades 13. Therefore, the cooling efficiency of the motor 20 is improved.

[0078] Since the interval D3 in the direction of the rotation axis 22 between the lower end portion of the auxiliary blade 13 and the portion of the motor flange 33 facing the lower end portion of the auxiliary blade 13 is ensured to be 5.0 mm or more, even if the centrifugal fan 10 vibrates slightly during operation, the lower end portion of the auxiliary blade 13 will not collide with the upper surface of the annular plate portion 33a of the motor flange 33. In addition, it is possible to prevent the jamming of foreign matter that has entered between the auxiliary blade 13 and the annular plate portion 33a, and the locking of the centrifugal fan 10 due to the freezing of the water that has entered between the auxiliary blade 13 and the annular plate portion 33a.

[0079] (Fluid analysis) Next, the fluid analysis results of the above embodiment and the comparative example will be described. In the comparative example, the outer end portion 13b of the auxiliary blade 13 and the outer end portion 11b of the main blade 11 are in the same position in the radial direction, and the portion of the tongue portion 30d facing the outer end portion 13b of the auxiliary blade 13 is released radially outward, so that the separation distance between the outer end portion 13b of the auxiliary blade 13 and the tongue portion 30d is made equal to the separation distance D2.

[0080] When comparing the flow rate that reflows from the downstream side to the upstream side of the air supply passage S1 beyond the tongue portion 30d between the above embodiment and the comparative example, the above embodiment had less than the comparative example. The fact that the reflowing flow rate is small means that the noise is reduced and the air supply efficiency is increased. Also, when comparing the static pressure in the air supply passage S1 between the above embodiment and the comparative example, they were substantially the same. That is, even if the separation distance D2 between the outer end portion 13b of the auxiliary blade 13 and the tongue portion 30d is set long, almost no decrease in static pressure is observed.

[0081] Also, in the case of the comparative example, it was confirmed that the static pressure was rising at the portion of the tongue corresponding to the auxiliary blade. Below the portion of the tongue corresponding to the auxiliary blade, it is considered that the pressure is relatively low, so air can easily flow in and the air flow can easily collide with the tongue. Therefore, it is presumed that the NZ sound is larger in the comparative example.

[0082] The above-described embodiment is merely an example in every respect and should not be construed in a limiting manner. Furthermore, all modifications and changes belonging to the equivalent scope of the claims are within the scope of the present invention.

Industrial Applicability

[0083] As described above, the blower for a vehicle air conditioner according to the present invention can be mounted and used, for example, in the passenger compartment of an automobile.

Explanation of Reference Numerals

[0084] 1 Blower for vehicle air conditioner 10 Centrifugal fan 11 Main blade 12 Blade support plate part 13 Sub-blade 13a Gate trace 20 Motor 30 Case 30d Tongue part 31a Bellows part 33 Motor flange 33d Annular wall part

Claims

1. A centrifugal fan, a motor that rotationally drives the centrifugal fan, and a blower for a vehicle air conditioner that houses the centrifugal fan and forms a blower passage around the centrifugal fan, wherein a bellmouth portion is provided on the suction side of the centrifugal fan in the case, a motor flange to which the motor is attached is provided on the side of the case opposite to the suction side of the centrifugal fan, a tongue portion is provided at the start portion of the blower passage in the case, the centrifugal fan is provided with a plurality of main blades that extend long in the rotational axis direction of the motor and are arranged at intervals in the circumferential direction, a plurality of sub - blades that are arranged at intervals in the circumferential direction on the motor flange side rather than the main blades, and a blade support plate portion that extends continuously in the circumferential direction of the rotational axis of the motor and supports the end portion of the main blade on the motor flange side, the blade support plate portion supports the end portion of the sub - blade on the main blade side and is interposed between the main blade and the sub - blade to divide the main blade and the sub - blade, in the radial direction of the rotational axis, the separation distance between the outer end portion of the sub - blade and the tongue portion is set longer than the separation distance between the outer end portion of the main blade and the tongue portion, in the radial direction of the rotational axis, the separation distance between the outer end portion of the blade support plate portion and the tongue portion is set shorter than the separation distance between the outer end portion of the sub - blade and the tongue portion, the dimension of the sub - blade in the radial direction of the rotational axis is set shorter than the dimension of the main blade in the radial direction of the rotational axis, in the radial direction of the rotational axis, the separation distance between the center line of the centrifugal fan and the inner end portion of the sub - blade is set longer than the separation distance between the center line of the centrifugal fan and the inner end portion of the main blade. A blower for a vehicle air conditioner.

2. The blower for a vehicle air conditioner according to claim 1, wherein the sub - blade protrudes from the blade support plate portion toward the motor flange side, a blower for a vehicle air conditioner.

3. The blower for a vehicle air conditioner according to claim 2, wherein an annular wall portion that protrudes toward the centrifugal fan side and extends annularly so as to surround the motor is provided on the motor flange so as to be closer to the blade support plate portion than the tip portion in the protruding direction of the sub - blade. A blower for a vehicle air conditioner in which a predetermined or greater gap is provided between an outer peripheral surface of the annular wall portion and the auxiliary blade.

4. In the blower for a vehicle air conditioner according to any one of Claims 1 to 3, a blower for a vehicle air conditioner in which a distance in the rotational axis direction between a tip portion in the protruding direction of the auxiliary blade and a portion of the motor flange facing the tip portion in the protruding direction of the auxiliary blade is set to 5.0 mm or more.

5. In the blower for a vehicle air conditioner according to any one of Claims 1 to 4, the centrifugal fan is an integrally molded product made of a resin material, gate traces are provided on the auxiliary blades that are circumferentially separated from each other among the plurality of auxiliary blades, a blower for a vehicle air conditioner in which the auxiliary blades provided with the gate traces are arranged at equal intervals in the circumferential direction.

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