Blower

Abstract

This blower comprises: a cylindrical casing, in both ends of which are formed intake ports through which air is drawn in, and having a circumferential wall of which the inner side serves as an air duct to an outlet port through which air is blown out; a main plate which is provided inside the casing so as to face the intake ports and which rotates about a rotary shaft, the axial direction of which is the direction extending to both ends of the casing; and an impeller which is provided on the main plate, rotates together with the main plate, and causes air drawn in from the intake ports to be blown out from the outlet port. The casing has: a first bulging part that takes a maximum value in terms of the distance from the rotary shaft to the circumferential wall in a central portion when viewed from the circumferential side; and a second bulging part that takes a maximum value in terms of the distance from the rotary shaft to the circumferential wall in a portion between the central portion and both end parts when viewed from the circumferential side. The distance from the rotary shaft to the circumferential wall in the second bulging part is longer than the distance from the rotary shaft to the circumferential wall at both ends.

Description

blower

[0001] The present disclosure relates to a blower including a casing, a main plate, and an impeller.

[0002] Conventionally, blowers including a casing, a main plate, and an impeller have been known. Among these, a multi-blade centrifugal blower includes an impeller with multiple blades arranged along the rotation axis on the outer periphery of a circular main plate, and a scroll casing that houses the impeller and forms a flow path that guides the airflow generated by the rotation of the impeller to an outlet. The flow direction and magnitude of the airflow at the outlet of such a multi-blade centrifugal blower are biased depending on the location of the outlet. To address this bias, Patent Document 1 discloses a double-inlet scroll casing that houses a double-inlet impeller with blades on both sides of the main plate, where the maximum distance between the impeller's rotation axis and the circumferential wall of the scroll casing is between the main plate of the impeller and the inlet, and where inlets are provided on both sides closer to the main plate than the midpoint between the main plate and the inlet. Patent Document 1 aims to improve blowing performance by uniforming the airflow distribution at the outlet.

[0003] Patent No. 7031061

[0004] However, the scroll casing disclosed in Patent Document 1 has a large space in the center near the main plate as viewed from the peripheral wall side, which slows down the air flow, but does not modify the air flow at both ends as viewed from the peripheral wall side, which is insufficient to uniformly distribute the air flow at the outlet.

[0005] The present disclosure has been made to solve the above-mentioned problems, and provides a blower that sufficiently uniforms the air flow distribution at the air outlet.

[0006] The blower of the present disclosure comprises a cylindrical casing having intake ports formed at both ends through which air is drawn, and the inside of the peripheral wall forming an air passage to the outlet ports from which air is blown out; a main plate disposed inside the casing opposite the intake ports and rotating with the direction extending to both ends of the casing as the axial direction of its rotation shaft; and an impeller disposed on the main plate and rotating together with the main plate to blow out the air drawn in through the intake ports from the outlet ports, wherein the casing has a first bulge portion which, when viewed from the circumferential side, has a maximum value in the distance from the rotation axis to the peripheral wall at the center, and a second bulge portion which, when viewed from the circumferential side, has a maximum value in the distance from the rotation axis to the peripheral wall between the center and both end portions, and the distance from the rotation axis to the peripheral wall at the second bulge portion is longer than the distance from the rotation axis to the peripheral wall at both end portions.

[0007] According to the present disclosure, in the second bulging portion where the distance from the rotation axis to the peripheral wall between the central portion and both end portions is the maximum value when viewed from the circumferential direction, the distance from the rotation axis to the peripheral wall is longer than the distance from the rotation axis to the peripheral wall at both end portions. Thus, the space is wide not only in the central portion but also between the central portion and both end portions. This allows the air flow to be slowed not only in the central portion but also between the central portion and both end portions. This allows the air flow distribution at the air outlet to be sufficiently uniform.

[0008] 1 is a circuit diagram showing an air conditioning apparatus according to embodiment 1. FIG. 2 is a perspective view showing a blower according to embodiment 1. FIG. 3 is a front transparent view showing a blower according to embodiment 1. FIG. 4 is an enlarged view of the front transparent view showing a blower according to embodiment 1. FIG. 5 is an enlarged view of a peripheral wall according to embodiment 1. FIG. 6 is a front view showing a diffuser according to embodiment 1. FIG. 7 is a graph showing the relationship between air volume and static pressure efficiency of a blower according to embodiment 1. FIG. 8 is an enlarged view of a peripheral wall according to a modified example of embodiment 1. FIG. 9 is a perspective view showing a blower according to embodiment 2. FIG. 10 is a front view showing a diffuser according to embodiment 2. FIG. 11 is a cross-sectional view in a plane perpendicular to the rotation axis of a casing according to embodiment 2.

[0009] Hereinafter, embodiments of a blower according to the present disclosure will be described with reference to the drawings. Note that the present disclosure is not limited to the embodiments described below. Furthermore, the dimensional relationships between components in the following drawings, including FIG. 2, may differ from the actual relationships. Furthermore, in the following description, terms indicating directions are used as appropriate to facilitate understanding of the present disclosure, but these terms are used only to explain the present disclosure and do not limit the present disclosure. Examples of terms indicating directions include "up," "down," "right," "left," "front," and "rear."

[0010] Embodiment 1. Figure 1 is a circuit diagram showing an air conditioning apparatus 1 pertaining to embodiment 1. The air conditioning apparatus 1 is a device that conditions the air in a space to be air-conditioned, and as shown in Figure 1, is equipped with an outdoor unit 2 and an indoor unit 3. The outdoor unit 2 is equipped with, for example, a compressor 6, a flow path switching device 7, an outdoor heat exchanger 8, an outdoor blower 9, and an expansion section 10. The indoor unit 3 is equipped with, for example, a heat exchanger 11 and a blower 12.

[0011] The refrigerant circuit 4 is configured by connecting a compressor 6, a flow switching device 7, an outdoor heat exchanger 8, an expansion section 10, and a heat exchanger 11 via refrigerant piping 5. The compressor 6 draws in low-temperature, low-pressure refrigerant, compresses it, and discharges it as high-temperature, high-pressure refrigerant. The compressor 6 is, for example, a capacity-controllable inverter compressor. The flow switching device 7 switches the direction of refrigerant flow in the refrigerant circuit 4 and is, for example, a four-way valve. The outdoor heat exchanger 8 exchanges heat between, for example, outdoor air and the refrigerant. The outdoor heat exchanger 8 functions as a condenser during cooling operation and as an evaporator during heating operation. The expansion section 10 is a pressure-reducing valve or expansion valve that reduces the pressure of the refrigerant and expands it. The expansion section 10 is, for example, an electronic expansion valve whose opening is adjustable.

[0012] The heat exchanger 11 exchanges heat between, for example, indoor air and a refrigerant. The heat exchanger 11 acts as an evaporator during cooling operation and as a condenser during heating operation. The blower 12 is a device that sends indoor air to the heat exchanger 11.

[0013] (Operation Modes, Cooling Operation) Next, the operation modes of the air conditioner 1 will be described. First, cooling operation will be described. In cooling operation, the refrigerant drawn into the compressor 6 is compressed by the compressor 6 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas refrigerant discharged from the compressor 6 passes through the flow switching device 7 and flows into the outdoor heat exchanger 8, which functions as a condenser. In the outdoor heat exchanger 8, the refrigerant exchanges heat with outdoor air sent by the outdoor blower 9, condensing and liquefying. The condensed liquid refrigerant flows into the expansion section 10, where it expands and is decompressed to become a low-temperature, low-pressure, two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant then flows into the heat exchanger 11, which functions as an evaporator. In the heat exchanger 11, the refrigerant exchanges heat with indoor air sent by the blower 12, evaporating and gasifying. At this time, the indoor air is cooled, and cooling is performed in the room. The evaporated refrigerant in a low-temperature, low-pressure gas state passes through the flow switching device 7 and is sucked into the compressor 6 .

[0014] (Operation Mode, Heating Operation) Next, the heating operation will be described. In the heating operation, the refrigerant drawn into the compressor 6 is compressed by the compressor 6 and discharged in a high-temperature, high-pressure gas state. The high-temperature, high-pressure gas refrigerant discharged from the compressor 6 passes through the flow path switching device 7 and flows into the heat exchanger 11, which functions as a condenser. In the heat exchanger 11, the refrigerant exchanges heat with the indoor air sent by the blower 12 and condenses to a liquid. At this time, the indoor air is heated, and heating is performed in the room. The condensed liquid refrigerant flows into the expansion section 10, where it expands and decompresses to become a low-temperature, low-pressure, two-phase gas-liquid refrigerant. The two-phase gas-liquid refrigerant then flows into the outdoor heat exchanger 8, which functions as an evaporator. In the outdoor heat exchanger 8, the refrigerant exchanges heat with the outdoor air sent by the outdoor blower 9 and evaporates to a gas. The evaporated low-temperature, low-pressure gas refrigerant passes through the flow path switching device 7 and is drawn into the compressor 6.

[0015] The air conditioner 1 does not have to have the flow path switching device 7. In this case, the air conditioner 1 becomes a dedicated cooling machine or a dedicated heating machine.

[0016] (Blower 12) Fig. 2 is a perspective view showing the blower 12 according to embodiment 1. Next, the blower 12 will be described in detail. As shown in Fig. 2, the blower 12 includes a casing 20, a main plate 30, an impeller 40, and a diffuser 50.

[0017] (Casing 20) The casing 20 is a cylindrical member having suction ports 13 formed at both ends for sucking in air, and the inside of a peripheral wall 21 forming an air passage to the air outlet 14 from which air is blown out. The openings of the perfectly circular cylinder form the suction ports 13, and the side surface of the cylinder forms the peripheral wall 21. The annular space between the peripheral wall 21 and the impeller 40 forms an air passage for air to flow from the impeller 40 to the air outlet 14.

[0018] (Main Plate 30) The main plate 30 is a plate-shaped member provided inside the casing 20 facing the suction port 13. The main plate 30 rotates around the axial direction of the rotation shaft 31, which is the direction extending to the two suction ports 13 at both ends of the casing 20.

[0019] (Impeller 40) The impellers 40 are multiple plate-shaped members provided on the peripheral edge of the main plate 30. The impellers 40 are provided at intervals on the peripheral edge of the main plate 30, with gaps formed between each impeller 40. Air drawn in through the suction port 13 passes through the gaps between the impellers 40 toward the outlet 14. The impellers 40 rotate together with the main plate 30, and blow out the air drawn in through the suction port 13 from the outlet 14.

[0020] (Diffuser 50) The diffuser 50 has a base end connected to the peripheral wall 21 of the casing 20 and a tip end formed with an air outlet 14. The diffuser 50 is a rectangular tubular member, with one opening connected to the peripheral wall 21 and the other opening serving as the air outlet 14. The diffuser 50 has a continuous connection portion 51 that is connected continuously to the peripheral wall 21, and a discontinuous connection portion 55 that extends from a tongue portion 56 that is discontinuously connected to the peripheral wall 21.

[0021] FIG. 3 is a front perspective view of the blower 12 according to the first embodiment, and FIG. 4 is an enlarged front perspective view of the blower 12 according to the first embodiment. FIG. 5 is an enlarged view of the peripheral wall 21 according to the first embodiment. FIG. 3 is a cross-sectional view of FIG. 2 taken along line A. As shown in FIGS. 3 to 5, the peripheral wall 21 of the casing 20 has a first bulge 22 and a second bulge 23. Here, the bulge refers to a portion that is convex outward from the casing 20. In FIG. 5, both the first bulge 22 and the second bulge 23 bulge outward from the dashed line connecting both ends of the peripheral wall 21 of the casing 20. The first bulge 22 is a portion at the center where the distance from the rotation axis 31 to the peripheral wall 21 is at a maximum value when viewed from the circumferential side. When viewed from the circumferential side, the first bulge 22 is located on an extension of the direction in which the main plate 30 extends. The second bulging portions 23 are portions where the distance from the rotation axis 31 to the peripheral wall 21 between the center and both end portions is at a maximum when viewed from the circumferential direction. In the first embodiment, there are two second bulging portions 23. That is, the peripheral wall 21 has three maximum values ​​due to the first bulging portion 22 and the two second bulging portions 23. The number of second bulging portions 23 is not limited to two, and may be three or more.

[0022] As shown in FIG. 3, the distance L from the rotation axis 31 to the peripheral wall 21 in the second bulging portion 23 ２ is the distance L from the rotation shaft 31 to the peripheral wall 21 at both ends. ０ The distance L from the rotation axis 31 to the peripheral wall 21 in the first bulging portion 22 is longer than １ Also, the distance L from the rotation shaft 31 to the peripheral wall 21 at both ends ０ That is, in the first embodiment, the three maximum values ​​formed by the first bulging portion 22 and the two bulging portions are all longer than the distance L from the rotation axis 31 to the peripheral wall 21 at both ends. ０ Here, the distance L from the rotation axis 31 to the peripheral wall 21 in the first bulging portion 22 is longer than １ is the distance L from the rotation shaft 31 to the peripheral wall 21 at both ends. ０ Whereas, 1.03≦L １ / L ０ The relational expression ≦1.3 holds true. In addition, the distance L from the rotation axis 31 to the peripheral wall 21 in the second bulging portion 23 is ２is the distance L from the rotation shaft 31 to the peripheral wall 21 at both ends. ０ Whereas, 1.03≦L ２ / L ０ The relational expression ≦1.3 holds true.

[0023] FIG. 6 is a front view of the diffuser 50 according to the first embodiment. FIG. 6 is a cross-sectional view taken along line B in FIG. 2 . The continuous connection portion 51 of the diffuser 50 has a first diffuser bulge portion 52 and a second diffuser bulge portion 53. The first diffuser bulge portion 52 is a portion at the center, viewed from the circumferential direction, where the distance from the rotation axis 31 to the continuous connection portion 51 takes a maximum value. The second diffuser bulge portion 53 is a portion at the center, viewed from the circumferential direction, where the distance from the rotation axis 31 to the continuous connection portion 51 takes a maximum value between the center and both end portions. In the first embodiment, there are two second diffuser bulge portions 53. That is, the continuous connection portion 51 has three maximum values ​​due to the first diffuser bulge portion 52 and the two second diffuser bulge portions 53. The number of second diffuser bulges 53 is not limited to two, but may be three or more.

[0024] Here, the first diffuser bulge portion 52 is provided contiguous with the first bulge portion 22. The second diffuser bulge portion 53 is also provided contiguous with the second bulge portion 23. That is, the distance from the rotation shaft 31 to the continuous connection portion 51 in the second diffuser bulge portion 53 is longer than the distance from the rotation shaft 31 to the continuous connection portion 51 at both ends. Also, the distance from the rotation shaft 31 to the continuous connection portion 51 in the first diffuser bulge portion 52 is longer than the distance from the rotation shaft 31 to the continuous connection portion 51 at both ends.

[0025] Here, the value obtained by dividing the distance from the rotation axis 31 to the continuous connection 15 in the second diffuser bulge 53 by the distance from the rotation axis 31 to the continuous connection 15 at both ends is 1.03 or more and 1.3 or less. Also, the value obtained by dividing the distance from the rotation axis 31 to the continuous connection 15 in the first diffuser bulge 52 by the distance from the rotation axis 31 to the continuous connection 15 at both ends is 1.03 or more and 1.3 or less.

[0026] Fig. 7 is a graph showing the relationship between air volume and static pressure efficiency of blower 12 according to embodiment 1. In Fig. 7, the horizontal axis represents air volume of blower 12, and the vertical axis represents static pressure efficiency. The comparative example in Fig. 7 is blower 12 that does not have first bulge portion 22 or second bulge portion 23. As shown in Fig. 7, the static pressure efficiency of blower 12 according to embodiment 1 is higher than the static pressure efficiency of blower 12 according to the comparative example over a wide range, from the air volume at which maximum efficiency is achieved to the larger air volume side.

[0027] According to the first embodiment, in the second bulge portion 23 where the distance from the rotation axis 31 to the peripheral wall 21 between the central portion and both end portions is the maximum value when viewed from the circumferential direction, the distance from the rotation axis 31 to the peripheral wall 21 is longer than the distance from the rotation axis 31 to the peripheral wall 21 at both end portions. In this way, the space is wide not only in the central portion but also between the central portion and both end portions. Therefore, it is possible to slow down not only the air flow in the central portion but also the air flow between the central portion and both end portions. This makes it possible to sufficiently uniformize the air flow distribution at the air outlet 14.

[0028] The diffuser 50 also has a first diffuser bulge 52 that has a maximum distance from the rotation axis 31 to the continuous connection 51 at the center, as viewed from the circumferential direction. The diffuser 50 also has second diffuser bulge 53 that has a maximum distance from the rotation axis 31 to the continuous connection 51 between the center and both end portions, as viewed from the circumferential direction. The distance from the rotation axis 31 to the continuous connection 51 at the second diffuser bulge 53 is longer than the distance from the rotation axis 31 to the continuous connection 51 at both end portions. This ensures that the air flow remains uniform even when the air moves from the casing 20 to the diffuser 50, thereby achieving a sufficiently uniform air flow distribution at the air outlet 14. The diffuser 50 does not necessarily have to have the first diffuser bulge 52 or the second diffuser bulge 53. In this case, the air flow is sufficiently uniformed by only the first bulging portion 22 and the second bulging portion 23 of the peripheral wall 21 .

[0029] The distance L from the rotation shaft 31 to the peripheral wall 21 at the second bulging portion 23 is the distance L from the rotation shaft 31 to the peripheral wall 21 at both ends.０ Whereas, 1.03≦L / L ０ When this relationship is satisfied, the effect of making the air flow uniform can be maximized.

[0030] (Modification) Fig. 8 is an enlarged view of the peripheral wall 21 according to a modification of the first embodiment. In Fig. 8, the second bulge portion 23 bulges outward from the dashed line connecting both ends of the peripheral wall 21 of the casing 20, but the first bulge portion 22 does not bulge outward from the dashed line connecting both ends of the peripheral wall 21 of the casing 20. That is, in the modification, the distance from the rotation shaft 31 to the peripheral wall 21 at the first bulge portion 22 is shorter than the distance from the rotation shaft 31 to the peripheral wall 21 at both ends. Thus, even if the maximum value of the first bulge portion 22 is shorter than the distance from the rotation shaft 31 to the peripheral wall 21 at both ends, the air flow distribution at the air outlet 14 can be sufficiently uniform as long as the maximum value of the second bulge portion 23 is longer than the distance from the rotation shaft 31 to the peripheral wall 21 at both ends.

[0031] Embodiment 2. Figure 9 is a perspective view showing a blower 12 according to embodiment 2. This embodiment 2 differs from embodiment 1 in that a portion having a maximum value is also present in discontinuous connection portion 55 extending from tongue portion 56 that is discontinuously connected to peripheral wall 21. In this embodiment 2, portions common to embodiment 1 are assigned the same reference numerals and description thereof will be omitted, and the description will focus on the differences from embodiment 1.

[0032] As shown in FIG. 9 , the blower 12 is connected to the main plate 30 via a rotary shaft 31 at one end of the casing 20 and includes a motor 60 that drives the main plate 30 to rotate.

[0033] FIG. 10 is a front view of a diffuser 50 according to the second embodiment. FIG. 10 is a cross-sectional view taken along line C in FIG. 9 . As shown in FIG. 10 , the discontinuous connection portion 55 of the diffuser 50 has a first tongue-side bulge 57 and a second tongue-side bulge 58. The first tongue-side bulge 57 and the second tongue-side bulge 58 are shaped to protrude outward from the casing 20. That is, the first tongue-side bulge 57 and the second tongue-side bulge 58 are shaped to be convex outward from the casing 20. In the second embodiment, there are two second tongue-side bulges 58. The second tongue-side bulge 58 on the suction port 13 side where the motor 60 is provided is referred to as second tongue-side bulge 58a, and the second tongue-side bulge 58 on the suction port 13 side where the motor 60 is not provided is referred to as second tongue-side bulge 58b. The number of second tongue-side bulges 58 is not limited to two, but may be three or more.

[0034] FIG. 11 is a cross-sectional view of the casing 20 according to the second embodiment taken along a plane perpendicular to the rotation shaft 31. FIG. 11( a) is a cross-sectional view of the casing 20 taken along a plane perpendicular to the rotation shaft 31, including the side of the casing 20 on which the motor 60 is installed. This view corresponds to FIG. 10( a). FIG. 11( b) is a cross-sectional view of the casing 20 taken along a plane perpendicular to the rotation shaft 31, including the second tongue-side bulge 58 a. This view corresponds to FIG. 10( b). FIG. 11( c) is a cross-sectional view of the casing 20 taken along a plane perpendicular to the rotation shaft 31, including a recess provided between the second tongue-side bulge 58 a and the first tongue-side bulge 57. This view corresponds to FIG. 10( c). FIG. 11( d) is a cross-sectional view of the casing 20 taken along a plane perpendicular to the rotation shaft 31, including the first tongue-side bulge 57. This view corresponds to FIG. 10( d). Figure 11(e) is a cross-sectional view of the casing 20 taken along a plane including the first tongue-side bulge 57 and perpendicular to the rotation axis 31. This corresponds to (e) of Figure 10.

[0035] The angle formed by a tangent line S1 that passes through the rotation axis 31 and touches the tongue portion 56 and a horizontal line S2 that passes through the rotation axis 31 is defined as θ. The length of a perpendicular line drawn from the point of contact with the tongue portion 56 to the horizontal line S2 that passes through the rotation axis 31 is defined as y. In other words, y is the distance between the horizontal line S2 that passes through the rotation axis 31 and the discontinuous connection portion 55 in a cross section perpendicular to the rotation axis.

[0036] As shown in Figures 11(a) to 11(e), as θ increases, y increases, and as θ decreases, y decreases. In a cross-sectional view of the casing 20 including the first tongue-side bulge 57 and taken along a plane perpendicular to the rotation axis 31, θ is small, resulting in a small y (Figure 11(d)). Similarly, in a cross-sectional view including the second tongue-side bulge 58, θ is small, resulting in a small y (Figures 11(b) and 11(e)). On the other hand, in a cross-sectional view of the casing 20 between the first tongue-side bulge 57 and the second tongue-side bulge, θ is large, resulting in a large y (Figure 11(c)). That is, the discontinuous connection 55 has three minimum values ​​due to the first tongue-side bulge 57 and the two second tongue-side bulges 58. Furthermore, when comparing the bulges, the smaller the y, the more they protrude outward from the casing 20. That is, the smaller y is, the larger the space inside the casing 20 becomes, and the more space there is for air to flow. ２ 11(e), which is a cross section including the second tongue-side bulging portion 58b. ５ 11(a) is a cross-sectional view including the side surface of the casing 20 on which the motor 60 is installed. １ Furthermore, in FIG. 11( d ), which is a cross section including the first tongue-side bulge 57, ４ 11(a) is a cross-sectional view including the side surface of the casing 20 on which the motor 60 is installed. １ is smaller than.

[0037] Here, the y line in FIG. 11(d) is a cross section including the first tongue-side bulging portion 57. ４ 11(a) is a cross-sectional view including the side surface of the casing 20 on which the motor 60 is installed. １ Whereas, 1.03≦y １ / y ４ 11(b), which is a cross section including the second tongue-side bulging portion 58a, the relation y ２ 11(e), which is a cross section including the second tongue-side bulging portion 58b. ５11(a) is a cross-sectional view including the side surface of the casing 20 on which the motor 60 is installed. １ Whereas, 1.03≦y １ / y ２ ≦1.3 and 1.03≦y １ / y ５ The relational expression ≦1.3 holds true.

[0038] 10, the y line in FIG. 11(b) is a cross section including the second tongue-side bulging portion 58a on the side where the motor 60 is installed. ２ is a cross section including the second tongue-side bulging portion 58b on the side where the motor 60 is not provided. ５ . In this way, the second tongue-side bulge 58 on the side where the motor 60 is installed is larger than the other parts. The cross-sectional area contributing to air intake is smaller in the suction port 13 on the side where the motor 60 is installed, and therefore air is more difficult to intake than in the suction port 13 on the side where the motor 60 is not installed. This affects the blow-out distribution of the sucked air. In the second embodiment, the blow-out distribution of air can be made uniform by changing the size of the second tongue-side bulge 58.

[0039] REFRIGERATION SYSTEM, 2 OUTDOOR UNIT, 3 INDOOR UNIT, 4 REFRIGERANTE CIRCUIT, 5 REFRIGERANTE PIPE, 6 COMPRESSOR, 7 FLOW CHANNEL SWITCHING DEVICE, 8 OUTDOOR HEAT EXCHANGER, 9 OUTDOOR BLOWER, 10 EXPANSION SECTION, 11 HEAT EXCHANGER, 12 BLOWER, 13 SUPPLY PORTION, 14 OUTPUT PORTION, 20 CASING, 21 CIRCUITAL WALL, 22 FIRST BULGE PORTION, 23 SECOND BULGE PORTION, 30 MAIN PLATE, 31 ROTATING SHAFT, 40 IMPELLER, 50 DIFFUSER, 51 CONTINUOUS JOINT PORTION, 52 FIRST DIFFUSER BULGE PORTION, 53 SECOND DIFFUSER BULGE PORTION, 55 DISCONTINUOUS JOINT PORTION, 56 TONGUE PORTION, 57 FIRST TONGUE-SIDE BULGE PORTION, 58, 58a, 58b SECOND TONGUE-SIDE BULGE PORTION, 60 MOTOR

Claims

1. A blower comprising: a cylindrical casing with intake ports formed at both ends for sucking in air, and the inside of a peripheral wall forming an air passage to an outlet port from which air is blown out; a main plate located inside the casing opposite the intake port and rotating with the direction extending to both ends of the casing as the axial direction of its rotation shaft; and an impeller located on the main plate and rotating together with the main plate to blow out the air sucked in through the intake port from the outlet port, wherein the casing has: a first bulge portion that, when viewed from the circumferential side, has a maximum value in the distance from the rotation axis to the peripheral wall at the center; and second bulge portions that, when viewed from the circumferential side, have a maximum value in the distance from the rotation axis to the peripheral wall between the center and both ends, wherein the distance from the rotation axis to the peripheral wall at the second bulge portion is longer than the distance from the rotation axis to the peripheral wall at both ends.

2. The distance L from the rotation axis to the peripheral wall at the second bulge ２ is the distance L from the rotation axis to the peripheral wall at both ends. ０ Whereas, 1.03≦L ２ / L ０ The blower according to claim 1, wherein the relational expression ≦1.3 is satisfied.

3. A blower according to claim 1 or 2, wherein the distance from the rotary shaft to the peripheral wall at the first bulging portion is longer than the distance from the rotary shaft to the peripheral wall at both end portions.

4. Distance L from the rotation axis to the peripheral wall at the first bulge １ is the distance L from the rotation axis to the peripheral wall at both ends. ０ Whereas, 1.03≦L １ / L ０ The blower according to claim 3, wherein the relational expression ≦1.3 is satisfied.

5. The blower according to any one of claims 1 to 4, further comprising a diffuser whose base end is connected to the peripheral wall of the casing and whose tip end is formed with the air outlet.

6. A blower according to claim 5, wherein the diffuser further has a continuous connection portion that is continuously connected from the peripheral wall, and the continuous connection portion has: a first diffuser bulge portion that, when viewed from the circumferential side, has a maximum value in the distance from the rotation axis to the continuous connection portion at the center, and a second diffuser bulge portion that, when viewed from the circumferential side, has a maximum value in the distance from the rotation axis to the continuous connection portion between the center and both end portions, and the distance from the rotation axis to the continuous connection portion at the second diffuser bulge portion is longer than the distance from the rotation axis to the continuous connection portion at both end portions.

7. A blower as described in claim 6, wherein the value obtained by dividing the distance from the rotation axis to the continuous connection portion at the second diffuser bulge portion by the distance from the rotation axis to the continuous connection portion at both ends is 1.03 or more and 1.3 or less.

8. A blower according to claim 6 or 7, wherein the distance from the rotation axis to the continuous joint at the first diffuser bulge is longer than the distance from the rotation axis to the continuous joint at both ends.

9. A blower according to claim 8, wherein the value obtained by dividing the distance from the rotation axis to the continuous connection portion at the first diffuser bulge portion by the distance from the rotation axis to the continuous connection portion at both ends is 1.03 or more and 1.3 or less.

10. A blower as claimed in any one of claims 5 to 9, wherein the diffuser further has a discontinuous connection portion extending from a tongue portion that is discontinuously connected to the peripheral wall, and the discontinuous connection portion has: a first tongue-side bulge portion at which, in a plane perpendicular to the rotation axis, the length of a perpendicular line drawn from a point of contact with the tongue portion at the central portion to a horizontal line passing through the rotation axis has a minimum value; and a second tongue-side bulge portion at which, in a plane perpendicular to the rotation axis, the length of a perpendicular line drawn from a point of contact with the tongue portion between the central portion and both end portions to a horizontal line passing through the rotation axis has a minimum value.

11. A blower as described in claim 10, wherein the length of a perpendicular line drawn from the point of contact between the second tongue-side bulge and the tongue to a horizontal line passing through the rotation axis is shorter than the length of a perpendicular line drawn from the point of contact between the tongue and the side surface of the casing to a horizontal line passing through the rotation axis.

12. A blower as described in claim 11, wherein the value obtained by dividing the length of a perpendicular line drawn from the point of contact with the tongue portion on the side of the casing to a horizontal line passing through the rotation axis by the length of a perpendicular line drawn from the point of contact with the tongue portion on the second tongue-side bulge to a horizontal line passing through the rotation axis is greater than or equal to 1.03 and less than or equal to 1.

3.

13. A blower as claimed in any one of claims 10 to 12, wherein the length of a perpendicular line drawn from the point of contact between the first tongue-side bulge and the tongue to a horizontal line passing through the rotation axis is shorter than the length of a perpendicular line drawn from the point of contact between the tongue and the side surface of the casing to a horizontal line passing through the rotation axis.

14. A blower as described in claim 13, wherein the value obtained by dividing the length of a perpendicular line drawn from the point of contact with the tongue portion on the side surface of the casing to a horizontal line passing through the rotation axis by the length of a perpendicular line drawn from the point of contact with the tongue portion on the first tongue-side bulge to a horizontal line passing through the rotation axis is equal to or greater than 1.03 and equal to or less than 1.

3.

15. A blower as claimed in any one of claims 10 to 14, further comprising a motor connected to the main plate via the rotary shaft at one end of the casing and driving the main plate to rotate, wherein the length of a perpendicular line drawn from the point of contact with the tongue at the second tongue-side bulge on the side where the motor is installed to a horizontal line passing through the rotary shaft is shorter than the length of a perpendicular line drawn from the point of contact with the tongue at the second tongue-side bulge on the side where the motor is not installed to a horizontal line passing through the rotary shaft.

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