Blower systems, refrigeration cycle systems, ventilation units, and air purifiers.

Abstract

The present invention provides a blower, a refrigeration cycle device, a ventilation unit, and an air purifier that can rotate a motor at a low speed for a long period of time, even when the ambient temperature around the motor driving the blower becomes high, and that can prevent abnormal wear in the bearings. [Solution] A blower according to one embodiment of the present invention comprises a stator, a rotor, a shaft, a bearing, a motor having a variable rotational speed, and a control unit that controls the rotational speed of the motor, wherein the control unit has a rotation mode that sets the rotational speed n [rpm] of the motor to a rotational speed that satisfies 50 ≤ n < 150, the bearing has an inner ring, an outer ring, a plurality of rolling elements provided in an annular bearing space formed between the inner ring and the outer ring, and urea-based grease filled in the bearing space, and the motor is capable of rotating in rotation mode when the ambient temperature t [°C] of the motor satisfies at least 30 ≤ t ≤ 40.

Description

TECHNICAL FIELD

[0001] The present invention relates to a blower device, a refrigeration cycle device, a ventilation unit, and an air cleaner. BACKGROUND ART

[0002] Blower devices that rotate an impeller using a motor are known. In recent years, such blower devices are required to be capable of operating the motor at a low rotational speed (for example, 150 rpm or less). However, if the motor is continuously operated for a long time while maintaining the low rotational speed, oil film formation becomes insufficient in the bearing of the motor, which causes a problem that abnormal wear occurs in the bearing.

[0003] As a means for solving this problem, Patent Document 1 discloses a blower device including a variable-speed motor whose rotating shaft (shaft) is supported by a bearing filled with a lubricant, and a control unit that drives the motor. The control unit drives the motor by lowering the lower limit rotational speed of the motor (for example, when the normal lower limit rotational speed is 300 to 500 rpm, the lower limit rotational speed is lowered to 100 to 290 rpm when the ambient temperature decreases) when the temperature of the bearing or the ambient temperature around the bearing drops below a predetermined threshold temperature (for example, 30 to 38°C). The blower device of Patent Document 1 utilizes the characteristic that when the temperature of the grease (base oil) in the bearing is low, the kinematic viscosity of the grease is high and the oil film thickness is easily maintained, so that the motor can be continuously operated for a long time at the low rotational speed only when the ambient temperature of the motor is low. PRIOR ART DOCUMENTS PATENT DOCUMENTS

[0004] PATENT DOCUMENT 1 Japanese Unexamined Patent Publication No. 7-128428 SUMMARY OF THE INVENTION PROBLEM TO BE SOLVED BY THE INVENTION

[0005] However, the invention described in Patent Document 1 has a problem in that the lower limit of the motor's rotational speed cannot be lowered unless the ambient temperature of the motor falls below a threshold temperature (e.g., 30°C). In other words, if the ambient temperature of the motor is high (e.g., above 30°C), operating the motor at a low speed for a long period of time may cause abnormal wear in the bearings.

[0006] In view of the above circumstances, the object of the present invention is to provide a blower, a refrigeration cycle device, a ventilation unit, and an air purifier that can rotate the motor at a low speed for a long time and prevent abnormal wear in the bearing, even when the ambient temperature of the motor driving the blower is high, such as exceeding 30°C. [Means for solving the problem]

[0007] To achieve the above objective, a blower according to one embodiment of the present invention comprises a stator, a rotor disposed inside the stator, a shaft to which the rotor is fixed, a bearing that rotatably supports the shaft, a motor having a variable rotational speed, and a control unit that controls the rotational speed of the motor, The control unit has at least one rotation mode in which the rotation speed n [rpm] of the motor satisfies the condition 50 ≤ n < 150. The bearing comprises an inner ring, an outer ring, a plurality of rolling elements provided in an annular bearing space formed between the inner ring and the outer ring, and urea-based grease filled in the bearing space. The above motor can rotate in the above rotation mode at least when the ambient temperature t [°C] of the motor satisfies the conditions of 30 ≤ t ≤ 40.

[0008] According to the above-described blower, the control unit has at least one rotation mode in which the rotational speed n [rpm] of the motor satisfies the condition 50 ≤ n < 150, and the bearing comprises an inner ring, an outer ring, a plurality of rolling elements provided in an annular bearing space formed between the inner ring and the outer ring, and urea-based grease filled in the bearing space. In other words, by using urea-based grease in the bearing, it is possible to suppress the generation of abnormal bearing noise caused by low-speed rotation, even when the ambient temperature t [°C] of the motor satisfies the condition 30 ≤ t ≤ 40 at low-speed rotation where the rotational speed n [rpm] of the motor is 50 ≤ n < 150.

[0009] An oxide film of carboxylic acid, formed by the oxidation of urea groups contained in the urea-based grease, may be formed on at least one surface of the inner ring, outer ring, and rolling element of the bearing described above.

[0010] The above urea-based grease comprises a base oil, an additive, and a thickener, the thickener comprising a urea group. The above base oil may have a kinematic viscosity ν of 40 [mm² / s] or higher at 40°C.

[0011] The above motor may also be capable of rotating in the above rotation mode when the ambient temperature t [°C] of the motor satisfies at least 25 ≤ t ≤ 45.

[0012] The lower limit rotational speed nmin [rpm] of the motor in the above rotation mode may be 50 ≤ nmin < 100.

[0013] The above-mentioned blower and, A refrigerant circuit is formed by sequentially connecting a compressor, condenser, pressure reducing device, and evaporator via refrigerant piping. Equipped with, The above-mentioned blower generates an airflow that passes through the above-mentioned condenser or evaporator. A refrigeration cycle device may also be used.

[0014] The above-mentioned refrigeration cycle device is The above blower generates an airflow that passes through the above condenser, The above motor is arranged on the downstream side of the above condenser in the flow of the above airflow passing through the above condenser, The above motor is driven in the above rotation mode while the airflow heat-exchanged by the above condenser passes around the above motor It may be a refrigeration cycle apparatus.

[0015] The above refrigeration cycle apparatus The above motor may be driven in the above rotation mode when the heat exchange intermediate temperature of the above condenser is 40°C or higher.

[0016] The above refrigeration cycle apparatus is an air conditioner having an outdoor unit and an indoor unit, The above outdoor unit includes an outdoor heat exchanger, the above compressor, and an outdoor blower, The above indoor unit includes a first indoor heat exchanger, a second indoor heat exchanger, and an indoor blower, The above control unit may cause the above outdoor heat exchanger and the above first indoor heat exchanger to function as condensers, and the above second indoor heat exchanger to function as an evaporator in the reheat dehumidification operation of the above air conditioner.

[0017] It may be a ventilation unit including the above blower.

[0018] It may be an air purifier including the above blower. Effects of the Invention

[0019] According to the present invention, it is possible to provide a blower, a refrigeration cycle apparatus, a ventilation unit, and an air purifier that can rotate the motor at low speed for a long period of time and prevent abnormal wear in the bearing even when the ambient temperature of the motor driving the blower increases. Brief Description of the Drawings

[0020] [Figure 1] It is a cross-sectional view of the motor of the blower according to the embodiment of the present invention. [Figure 2] This is a diagram showing the bearings of the motor described above. [Figure 3] This is a block diagram of the motor and control unit of the blower described above. [Figure 4] The above diagram illustrates the phenomenon of abnormal noise occurring from the bearing. (A) shows the case when the ambient temperature of the motor is high and the rolling elements rotate at a low speed, and (B) shows the case when the ambient temperature of the motor is low and the rolling elements rotate at a low temperature and low speed. [Figure 5] This diagram shows the generation of abnormal noise due to changes in the rotational speed of the motor mentioned above. [Figure 6] The above diagram shows the relationship between the bearing and grease, with (A) showing the state before rotation and (B) showing the state during rotation. [Figure 7] This figure shows the relationship between the friction coefficient and lubrication state of the bearing described above. [Figure 8] This is a conceptual diagram showing a refrigeration cycle system (air conditioning system) equipped with the blower device of the present invention. [Figure 9] This is a cross-sectional view of the main part of the heat source side unit (outdoor unit) of a refrigeration cycle system (air conditioning system) equipped with the blower device of the present invention, viewed from the side. [Figure 10] This is a cross-sectional view of an air purifier equipped with the blower device of the present invention. [Figure 11] This is a conceptual diagram showing a ventilation unit equipped with the blower device of the present invention. [Figure 12] This is a conceptual diagram showing a refrigeration cycle system (air conditioning system) that performs reheat dehumidification operation and is equipped with the blower device of the present invention. [Modes for carrying out the invention]

[0021] Next, embodiments of the present invention will be described with reference to the drawings. In the following drawings, identical or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and may differ from reality. Therefore, specific components should be determined by referring to the following description.

[0022] Furthermore, the embodiments described below illustrate devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention does not limit the shape, structure, arrangement, etc. of the components to those described below. The technical concept of the present invention can be modified in various ways within the technical scope defined by the claims described in the patent claims.

[0023] The following describes a blower F according to one embodiment of the present invention.

[0024] Figure 1 is a cross-sectional view of the motor 1 of a blower F according to an embodiment of the present invention, and Figure 2 is a diagram showing the bearings of the motor 1 (first bearing 7, second bearing 8). Figure 3 is a block diagram of the motor 1 and control unit 100 of the blower F. As shown in Figure 1, the motor 1 is, for example, a brushless DC motor. In this embodiment, the motor 1 is used to rotate the impeller 300 of a blower F mounted on a refrigeration cycle device, particularly the heat source side unit of the refrigeration cycle device (for example, the outdoor unit 210 of an air conditioner 200 described later).

[0025] As shown in Figure 3, the blower F comprises a control unit 100, a blower (fan) 150, and a temperature sensor S. The blower (fan) 150 comprises a motor 1 and an impeller 300 driven by the motor 1.

[0026] (Motor and blower) Motor 1 is a variable-speed inverter motor comprising a stator 2, a rotor 3, a shaft 6, bearings (first bearing 7, second bearing 8), a bracket 4, a resin casing 10, and a circuit board 5.

[0027] (rotor) The rotor 3 has an annular permanent magnet section 31 and a rotor body 30. The rotor body 30 has an outer circumferential surface and an inner circumferential surface. The permanent magnet section 31 is fixed to the outer circumferential surface of the rotor body 30. The rotating shaft 6 is fixed to the inner circumferential surface of the rotor body. As a result, the rotating shaft 6 rotates in conjunction with the rotor body 30.

[0028] The rotor 3 is a surface magnet type in which a permanent magnet section 31 is fixed in an annular shape to the outer circumferential surface. The permanent magnet section 31 is formed in an annular shape by multiple (for example, 8 or 10) permanent magnets such that the north pole and south pole alternate at equal intervals in the circumferential direction. The permanent magnet section 31 is typically formed from a metal sintered body such as an Nd-Fe-B alloy, but a plastic magnet formed in an annular shape by solidifying magnet powder with resin may also be used.

[0029] (stator) The stator 2 comprises a stator core 21 having a cylindrical yoke portion and a plurality of teeth portions extending inward from the yoke portion, and windings (coils) 22 wound around the teeth portions. The stator core 21 is a laminate of plates made of a soft magnetic material such as a plurality of electromagnetic steel sheets. The outer surface of the stator 2 (stator core 21) is covered with a resin casing 10 (see Figure 1). The stator 2 is arranged such that the permanent magnet portion 31 of the rotor 3 faces the stator core 21 of the stator 2 in the radial direction with an air gap (magnetic gap) between them.

[0030] (Resin outer shell) The resin casing 10 is formed from an insulating resin material. As shown in Figure 1, it is formed in a hollow cylindrical shape with an open end 10A at one end in the axial direction C (in this embodiment, the end opposite to the output end 61 of the shaft 6). Here, the output end 61 is the end of the shaft 6 located on the load side (the side connected to the load) of the motor 1, and functions as an impeller fixing part to which the impeller 300, described later, is attached. As described above, the resin casing 10 is integrally molded with the stator 2. The resin material forming the resin casing 10 is not particularly limited, and for example, it is formed from BMC (Bulk Molding Compound: unsaturated polyester resin).

[0031] Furthermore, the resin outer casing 10 has a mounting surface 9. The mounting surface 9 is formed on the inner circumferential surface of the resin outer casing 10, is an inner circumferential plane perpendicular to the axial direction, and is located on the opposite side of the output end 61 of the rotating shaft 6, separated from the rotor 3 by a gap in the axial direction. The mounting surface 9 supports the circuit board 5, which will be described later. The mounting surface 9 may be formed continuously in the circumferential direction on the inner circumferential surface of the resin outer casing 10, or it may be formed at multiple locations spaced apart in the circumferential direction.

[0032] The resin casing 10 further has a second bearing housing portion 10C for housing a second bearing 8, which will be described later. The general shape of the second bearing housing portion 10C is a cylindrical shape with one end closed, centered on the axis C. The second bearing housing portion 10C is provided at the bottom portion 10B of the resin casing 10, opposite to the open end portion 10A.

[0033] (Circuit board) The circuit board 5 includes a wiring board and an electronic component that generates heat when energized, mounted on the surface of the wiring board (the surface opposite to the output end 61 of the rotating shaft 6). The circuit board 5 is generally disc-shaped, and its peripheral edge is supported on the mounting surface 9 and fixed by means of adhesive, bonding, screw fastening, soldering, etc.

[0034] Electronic components that generate heat when energized are mainly semiconductor components such as power supply ICs and motor drive current control ICs, but passive components such as capacitors may also be included. In addition to electronic components, other components such as connector components that connect to the power cable are mounted on the wiring board, but these are not shown in the illustration. The power cable is connected to a power supply (not shown) through a cable insertion section formed in a predetermined angular range in the circumferential direction near the open end 10A of the resin casing 10.

[0035] (bracket) The bracket 4 has a first bearing housing portion 41 and a disc portion 42. The heat sink 4 is attached to and fixed to the open end 10A of the resin outer shell 10. The heat sink 4 is made of a metal material with excellent thermal conductivity, such as aluminum. The heat sink 4 is molded, for example, by die casting.

[0036] The heat sink 4 functions as a cover member (bracket) that closes the opening of the resin outer casing 10 by covering the open end 10A of the resin outer casing 10. The heat sink 4 is fixed to the open end 10A of the resin outer casing 10 using a plurality of screw members (not shown).

[0037] (Bearing) As shown in Figure 2, the first bearing 7 is formed in a generally annular shape. The first bearing 7 is a ball bearing having an outer ring 71, an inner ring 72, a cage 73, rolling elements (balls) 74, and grease G. The second bearing 8 is a ball bearing having an outer ring 81, an inner ring 82, a cage 83, rolling elements 84, and grease G.

[0038] As shown in Figure 2, the outer ring 71 of the first bearing 7 is annular and fixed to the bracket 4 (first bearing housing 41). The inner ring 72 of the first bearing 7 is annular and fixed to the opposite side of the output end 61 of the rotating shaft 6. The multiple rolling elements 74 of the first bearing 7 are provided in the bearing space W1, which is an annular space formed between the inner ring 72 and the outer ring 71. The cage 73 is provided in the bearing space W1 and holds the rolling elements 74 so that they can roll freely. The cage 73 also holds the multiple rolling elements 74 at a constant interval in the circumferential direction of the first bearing 7. The grease G is a semi-solid lubricant containing a base oil, additives and a thickener, and is filled into the bearing space W1.

[0039] The outer ring 81 of the second bearing 8 is formed in an annular shape and fixed to the resin outer casing 10 (second bearing housing 10C), and the inner ring 82 of the second bearing 8 is fixed to the output end 61 of the rotating shaft 6. The multiple rolling elements 84 of the second bearing 8 are provided in the bearing space W2, which is an annular space formed between the inner ring 82 and the outer ring 81. The cage 83 is provided in the bearing space W2 and holds the rolling elements 84 so that they can roll freely. The cage 83 also holds the multiple rolling elements 84 at a constant interval in the circumferential direction of the second bearing 8. Grease G is a semi-solid lubricant containing a base oil, additives and a thickener, and is filled into the bearing space W2. In this embodiment, urea grease is used as the grease G.

[0040] When external pressure is applied to the grease G, the base oil becomes fluid due to shear force, and it functions as the lubricant described above. In other words, as the rolling elements 74 rotate, pressure is applied to the grease G, and the base oil seeps out from the grease G, forming an oil film between the outer rings 71, 81 and inner rings 72, 82 and the rolling elements 74. This allows the rolling elements 74 to rotate smoothly.

[0041] The urea grease used as grease G in the examples is a grease containing a urea compound having a urea group (-NHCONH-) in its molecule as a thickener. The urea compound used as a thickener is preferably a diurea having two urea groups in its molecule, but compounds with three or more urea groups (e.g., triurea or tetraurea) may also be used. Furthermore, while aliphatic diurea is used as the diurea in the examples, aromatic diurea may also be used. Urea grease is characterized by its long lifespan even at high temperatures because it does not contain metal groups in the molecule of the thickener, thus preventing degradation due to oxidation of the base oil.

[0042] The urea grease in the example contains 5-30% by weight of urea compound and 95-70% by weight of base oil relative to the total amount of grease, but is not limited to this. As an example of a method for producing urea compounds, a method is known in which diurea is obtained by reacting a diisocyanate compound, which is also a raw material for polyurethane, with an amine compound.

[0043] The rotating shaft 6 is supported by a first bearing 7 and a second bearing 8 so as to be rotatable with respect to the bracket 4 and the resin casing 10, with its axis C as the central axis.

[0044] In this embodiment, grease G includes either a first urea grease G1 or a second urea grease G2 as a urea grease. The first urea grease G1 has a base oil whose main component is a synthetic hydrocarbon, and the kinematic viscosity ν of the base oil at 40°C is 48 [mm²]. 2The second urea grease G2 has a base oil whose main component is ester oil, and the kinematic viscosity ν of the base oil at 40°C is 100 [mm²]. 2 The thickener is urea grease containing a urea compound.

[0045] As shown in Figure 1 and Figure 9 described later, the impeller 300 is fixed to the output end 61 (impeller fixing part) of the shaft 6 and rotates in synchronization with the rotation of the rotating shaft 6.

[0046] (Temperature sensor) The temperature sensor S detects the ambient temperature of the motor 1. As shown in Figure 9, the temperature sensor S is attached to, for example, the outdoor heat exchanger 250, but it is not limited to this, and any sensor that can measure a temperature equivalent to the ambient temperature of the motor 1 is acceptable. In this embodiment, for example, a thermistor is used for the temperature sensor S, but it is not limited to this. In this embodiment, the case in which the blower F is equipped with the temperature sensor S is illustrated, but the blower F does not necessarily have to be equipped with the temperature sensor S.

[0047] (Control Unit) The control unit 100 includes a computer having a processor such as a CPU and a memory device such as ROM or RAM. The control unit 100 includes an inverter circuit that controls the rotational speed of the motor 1 by controlling the frequency of the pulse voltage supplied to the motor 1. The control unit 100 outputs a control signal for controlling the pulse voltage frequency to the motor 1 via a signal line. In other words, the control unit 100 can control the rotational speed of the motor 1 using a control signal.

[0048] The control unit 100 has a low-speed rotation mode (rotation mode, first rotation mode) for rotating the motor 1 at a low speed, and a high-speed rotation mode (second rotation mode) for rotating the motor 1 at a high speed. The control unit 100 controls the rotation speed of the motor 1 using either the low-speed rotation mode or the high-speed rotation mode.

[0049] The low-speed rotation mode is a rotation mode in which the rotation speed n [rpm] of motor 1 satisfies the condition 50 ≤ n < 150, and the high-speed rotation mode is a rotation mode in which the rotation speed n [rpm] of motor 1 satisfies the condition 150 ≤ n.

[0050] In other words, the control unit 100 rotates motor 1 at a rotational speed n [rpm] where 50 ≤ n < 150, causing motor 1 to rotate in low-speed mode. The control unit 100 also rotates motor 1 at a rotational speed n [rpm] where 150 ≤ n, causing motor 1 to rotate in high-speed mode.

[0051] The control unit 100 may control the rotation speed of the motor 1 based on the detection result of the temperature sensor S described above. For example, in this embodiment, the control unit 100 allows the motor 1 to rotate in low-speed rotation mode when the temperature t [°C] detected by the temperature sensor S satisfies 20 ≤ t ≤ 50. Therefore, in this embodiment, the motor 1 can rotate in low-speed rotation mode at least when the ambient temperature t [°C] of the motor 1 satisfies 30 ≤ t ≤ 40.

[0052] In this embodiment, the rotation speed of the motor 1 is controlled based on the detection result of the temperature sensor S. However, this is not the only option, and the control unit 100 may rotate the motor 1 in low-speed rotation mode regardless of the detection result of the temperature sensor S. In this case, it is sufficient that the motor 1 is always capable of rotating in low-speed rotation mode when the temperature detected by the temperature sensor S is in the range of 30°C to 40°C.

[0053] Furthermore, the blower unit F itself does not need to have a temperature sensor S. It is sufficient that the ambient temperature t [°C] of the motor 1 is high (30 ≤ t ≤ 40) when the ambient temperature of the motor 1 is measured by an external temperature sensor, for example, one installed separately from the outdoor unit 210 of the air conditioner 200, while the motor 1 is operating in low-speed rotation mode. In other words, the motor 1 equipped with the blower unit F can rotate in low-speed rotation mode across the entire temperature range of 30°C to 40°C, where the actual ambient temperature t [°C] is.

[0054] In this embodiment, the temperature detected by the temperature sensor S is considered to be the ambient temperature t [°C] of the motor 1. However, if there is a discrepancy between the temperature detected by the temperature sensor S and the actual ambient temperature t [°C] of the motor 1, the temperature detected by the temperature sensor S may be corrected to represent the actual ambient temperature t [°C] of the motor 1.

[0055] Here, Figure 4 illustrates the phenomenon in which abnormal noise is generated from the bearing (first bearing 7) when the ambient temperature of the motor 1 is high. (A) shows the case when the ambient temperature of the motor 1 is high and the rolling elements 74 are rotating at a low speed, and (B) shows the case when the ambient temperature of the motor 1 is low and the rolling elements 74 are low temperature and rotating at a low speed. The arrows shown in Figure 4 indicate the direction of rotation of the rolling elements.

[0056] As shown in Figure 4, the grease G is pressured by the rotating rolling elements 74, causing the base oil to seep out. As shown in Figure 4(B), when the ambient temperature of the motor 1 is low (for example, 20°C), the kinematic viscosity of the lubricant (base oil) in the bearing is high, and the oil film thickness increases. Therefore, at low rotational speeds (rotational speed n [rpm] is 50 ≤ n < 150) when the pressure on the grease G is small, an oil film of sufficient thickness is formed between the rolling elements 74 and the outer ring 71, allowing the rolling elements 74 to rotate smoothly.

[0057] On the other hand, as shown in Figure 4(A), when the ambient temperature of the motor 1 is high (for example, 40°C), the kinematic viscosity of the lubricant (base oil) in the bearing decreases, and the oil film thickness becomes smaller. Furthermore, at low rotational speeds (rotational speed n [rpm] is 50 ≤ n < 150), the pressure on the grease G is small. As a result, less lubricant (base oil) seeps out from the grease G, and the kinematic viscosity of the lubricant (base oil) decreases, leading to a problem where an oil film of sufficient thickness is not formed between the rolling elements 74 and the outer ring 71, resulting in oil film breakdown. In such cases where the ambient temperature of the motor 1 is high and oil film breakdown is likely to occur, the motor 1 of this embodiment can effectively suppress the generation of abnormal noise by using urea grease (first urea grease G1 or second urea grease G2) as grease G.

[0058] The above explanation using Figure 4 described the relationship between the rolling element 74 and the outer ring 71, but of course, it is not limited to this, and the above-mentioned problem also occurs with the rolling element 74 and the inner ring 72. Furthermore, the same problem described above occurs not only with the first bearing 7, but also with the second bearing 8.

[0059] Here, Figure 5 shows whether or not abnormal noise occurs due to differences in the rotational speed of motor 1 when motor 1 is driven continuously for a long period of time. Figure 6 shows the internal state of bearing 7 when grease G, which is a urea grease, is used, with Figure 6(A) showing the state before rotation and Figure 6(B) showing the state during rotation. Figure 7 shows the relationship between the friction coefficient of the bearing and the lubrication state.

[0060] The lithium-based lubricant shown in Figure 5 refers to the lithium grease used as a comparative example. Lithium grease is a semi-solid lubricant containing a base oil, additives, and a thickener, and specifically refers to lithium soap grease in which lithium soap is used as the thickener. More specifically, the lithium soap grease used as a comparative example has an ester oil as the main component of the base oil, and the kinematic viscosity ν of that base oil at 40°C is 26 [mm²]. 2 We used something that is [ / s].

[0061] Figure 5 shows the noise level measured using a vibration noise analysis system (manufacturer: Bruel & Kjar, software: PULS, front-end: Type 3160-A-042) while motor 1 was rotating with the blower F shown in Figure 9 (described later). Here, the mass of the impeller 300 (propeller fan) is approximately 1.5 [kg], the axial load on bearings 7 and 8 in Figure 1 is approximately 41 [N], the radial load on bearing 7 is approximately 21 [N], and the radial load on bearing 8 is approximately 36 [N]. The ambient temperature of motor 1 during noise measurement was 52 degrees Celsius. The vertical axis represents the noise OA (overall) value [dB(A)], and the horizontal axis represents the time [h] during which motor 1 was continuously rotated. In the legend of Figure 5, "lithium-based" indicates that the lithium grease described above was used as the grease, and the experiment was conducted with the rotation speed fixed at 150 [rpm] during continuous rotation. Furthermore, "urea-based" in the legend indicates that the second urea grease described above was used as the grease, and the experiment was conducted with the rotational speed fixed at 150 [rpm], 100 [rpm], and 50 [rpm], respectively. Table 1 below shows whether or not acoustic degradation occurred when a motor using lithium grease and a motor using the second urea grease were continuously rotated for 10,000 hours, and the rotational speed [rpm] at which the motors were continuously rotated during that time. In Table 1, "×" indicates that acoustic degradation occurred (increased noise occurred) under that condition, and "○" indicates that there was no acoustic degradation (no increase in noise occurred) under that condition.

[0062] [Table 1]

[0063] As shown in Figure 5 and Table 1, with the lithium-based grease, when continuously rotated at a rotation speed of 150 rpm, the noise level (OA) gradually began to rise after the continuous rotation time exceeded 1000 hours, and at 2200 hours, the noise level (OA) increased by approximately 6 dB(A) (acoustic deterioration). On the other hand, with the second urea grease, even when continuously operated for 10000 hours at rotation speeds of 200 rpm, 150 rpm, 100 rpm, and 50 rpm, no increase in noise level (acoustic deterioration) with increasing continuous rotation time, as seen with the lithium-based grease, was observed.

[0064] Here, we will consider the reasons for the results shown in Figure 5 and Table 1. The parameter Λ is a measure of the degree of metal-to-metal contact and is calculated as Λ = oil film thickness (for example, the thickness of the oil film formed between the outer ring 71 and the rolling element 74) [mm] ÷ surface roughness (for example, the surface roughness of the outer ring 71 or the rolling element 74) [mm]. Generally, when Λ < 1, boundary lubrication occurs (a lubrication state in which metal-to-metal contact occurs locally). When 1 < Λ < 3, mixed lubrication occurs (a state in which boundary lubrication and fluid lubrication coexist). Furthermore, when 3 < Λ, fluid lubrication occurs (a lubrication state in which the two surfaces (for example, the outer ring 71 and the rolling element 74) are completely separated by a fluid film).

[0065] In lithium-based lubrication (lithium grease), when the engine is continuously rotated at 150 rpm for 2200 hours, the noise level (OA) increases by 6 dB compared to immediately after the start of continuous rotation. This suggests that boundary lubrication occurs when the noise level (OA) begins to increase, i.e., when the continuous rotation time exceeds 1000 hours. At this point, the parameter Λ is estimated to be Λ < 1.

[0066] On the other hand, with the urea-based grease (second urea grease G2), the noise OA value when continuously rotated at 150 rpm for 10,000 hours is equivalent to the noise OA value immediately after starting continuous rotation at 150 rpm (0 hours). Also, the noise OA value when continuously rotated at 50 rpm for 10,000 hours is equivalent to the noise OA value immediately after starting continuous rotation at 50 rpm (0 hours). Furthermore, the noise OA value when continuously rotated at 50 rpm is equivalent to the noise OA value when continuously rotated at 150 rpm. In other words, with the urea-based grease, when continuously rotated in the range of 50 rpm to 150 rpm, there is no increase in noise even if the continuous rotation time increases. Furthermore, since the parameter Λ in this case is 1 < Λ < 3, a state of temporary metal-to-metal contact should have continued for a long time. However, as shown in Figure 5, no increase in noise occurred with increasing continuous rotation time. From this, it can be concluded that when a urea-based grease (second urea grease G2) is used, metal-to-metal contact can be suppressed even if the parameter Λ is in the range of 1 < Λ < 3.

[0067] When lithium-based grease (lithium grease) is used as the grease, the change in the composition of the thickener contained in the lithium grease due to the frictional heat generated by the rotation of the rolling elements 74 is mainly oxidation only. However, when urea-based grease (first urea grease G1, second urea grease G2) is used as the grease, the change in the composition of the thickener in the urea grease due to the frictional heat generated by the rotation of the rolling elements 74 is not only oxidation but also hardening.

[0068] Here, as shown in Figure 6, the hardening of grease G is a phenomenon in which the urea component (urea compound) U attached to the metal surface oxidizes and forms a film on the metal surface. More specifically, the urea group (-NHCONH-) contained in the urea grease attached to the metal surface oxidizes and changes to a carboxylic acid (-NHCOOH), so that the metal surface is protected by a film of carboxylic acid. In this embodiment, the oxidized urea component U of grease G adheres to the rolling element 74, the outer ring 71, and the inner ring 72 (the oxidized urea component U also adheres to the outer ring 81 and the inner ring 82 in the same way as the outer ring 71 and the inner ring 72). In other words, since the metal surface (rolling element 74, outer ring 71, and inner ring 72) is protected by the oxidized urea component U (carboxylic acid), even if the rolling element 74 rotates at a low speed, direct contact (metal contact) with the outer ring 71 (and inner ring 72, and also outer ring 81 and inner ring 82) can be suppressed.

[0069] Therefore, even in the boundary lubrication region (Λ<1) or the mixed lubrication region (1<Λ<3), it is presumed that by using a urea-based grease (urea grease) as the grease, as in this embodiment, direct contact between metals can be suppressed by the film of urea component U that adheres to the metal surface. In this way, by using a urea-based grease (first urea grease G1, second urea grease G2) as the grease, the generation of abnormal noise due to metal contact can be suppressed even when the motor 1 is operated continuously for a long time at low speed. Furthermore, by suppressing metal contact within the bearing, damage to the bearing can be suppressed.

[0070] Figure 7 is a conceptual diagram showing the Stribeck curve. As shown in Figure 7, the vertical axis represents the coefficient of friction within the bearing (for example, the coefficient of friction between the outer ring 71 and the rolling elements 74), and the horizontal axis represents the bearing constant, which changes depending on the viscosity of the grease, the rotational speed, and the load.

[0071] As shown in Figure 7, in the boundary lubrication region (Λ<1) and the mixed lubrication region (1<Λ<3), the higher the viscosity of the grease, the lower the coefficient of friction. Furthermore, the lower the rotational speed [rpm], the higher the coefficient of friction, and the greater the load applied to motor 1, the higher the coefficient of friction. In other words, even at the same rotational speed and load, the kinematic viscosity of the base oils of the first and second urea greases is higher than that of the base oil of the lithium grease, so the coefficient of friction is lower when using urea grease than when using lithium grease. That is, by using urea grease, it becomes possible to operate continuously for a long time even at lower rotational speeds than when using lithium grease.

[0072] In this embodiment, the blower F, with the configuration described above, can continuously operate (maintain) the motor 1 in low-speed rotation mode for a period longer than 5 hours. Furthermore, in this embodiment, since the blower F can continuously operate (maintain) the motor 1 in low-speed rotation mode for a period longer than 24 hours, it is possible to operate it all day long.

[0073] Furthermore, in this embodiment, by using urea grease (second urea grease), continuous operation for 10,000 hours was performed at rotational speeds of 200 rpm, 150 rpm, 100 rpm, and 50 rpm. Even when the ambient temperature of the motor 1 reached 52°C, no increase in noise OA value (deterioration of sound) associated with increased continuous rotation time, as seen with lithium-based greases, was observed. Generally, the viscosity (kinematic viscosity) of the base oil of grease decreases with increasing temperature of the base oil. Therefore, if no increase in noise OA value is observed (no abnormal wear occurs in the bearing) even when the ambient temperature of the motor 1 is 50°C, the oil film thickness increases when the ambient temperature of the motor 1 is lower (for example, 30°C, 40°C). Thus, it can be said that abnormal wear in the bearing is prevented in the range where the ambient temperature of the motor 1 is 50°C or lower.

[0074] [Table 2]

[0075] Table 2 shows whether or not there was any deterioration in sound quality when the motor using lithium grease in the comparative example and the motor using the second urea grease in this embodiment were operated at a low speed of 50 rpm, as well as the ambient temperature of the motor at that time. In Table 2, "×" indicates that deterioration in sound quality occurred (increased noise occurred) under those conditions, and "○" indicates that there was no deterioration in sound quality (no increase in noise occurred) under those conditions.

[0076] As shown in Table 2, in the comparative example motor using lithium grease, no deterioration in sound quality occurred when the ambient temperature of the motor was between 20°C and 30°C, but deterioration in sound quality occurred under conditions where the ambient temperature exceeded 30°C. On the other hand, in the motor 1 using the second urea grease of this embodiment, deterioration in sound quality did not occur not only when the ambient temperature t[°C] of the motor 1 was between 20°C and 30°C, but also when the ambient temperature was in the range of 30°C to 50°C, and abnormal wear in the bearing was prevented.

[0077] Therefore, in this embodiment, even when the ambient temperature of the motor driving the blower F is high (ambient temperature t [°C] is 30 ≤ t ≤ 40), the motor 1 can be rotated at a low speed for a long time, and abnormal wear in the bearing can be prevented. In other words, even if the ambient temperature of the motor becomes high (for example, due to exposure to air that has passed through a condenser) to 30°C or higher and 40°C or lower, causing the temperature of the lubricating oil in the bearing to rise, the kinematic viscosity to decrease, and the oil film thickness to decrease, using urea-based grease can form an oxide film, which suppresses metal-to-metal contact in the bearing, and the rotation speed of the blower motor can be reduced to a low speed (for example, 150 rpm or less) while preventing the occurrence of abnormal wear (abnormal noise) in the bearing.

[0078] In this embodiment, the base oil has a kinematic viscosity ν of 40 [mm] at 40°C. 2 The viscosity is ≥ [ / s]. This makes it less likely for the oil film to break down, even when the ambient temperature of motor 1 is high, because the kinematic viscosity is high.

[0079] In this embodiment, the control unit 100 controls the motor to operate in the rotation mode described above while the ambient temperature t [°C] of the motor satisfies 25 ≤ t ≤ 45. This allows the motor 1 to be driven by the control unit 100 in the rotation mode described above even in a high-temperature environment. Furthermore, the control unit 100 can also control the motor to operate in the rotation mode described above while the ambient temperature t [°C] of the motor satisfies 20 ≤ t ≤ 50.

[0080] In this embodiment, motor 1 is described as an inner rotor type brushless DC motor in which a cylindrical rotor 3 having a permanent magnet is rotatably arranged radially inside a cylindrical stator 2 that generates a rotating magnetic field. However, motor 1 is of course not limited to this, and may be other motors such as an outer rotor type brushless DC motor or an AC motor.

[0081] [Refrigeration cycle equipment] Figure 8 is a refrigerant circuit diagram showing a refrigeration cycle system equipped with the blower F of the present invention. The refrigeration cycle system is applied to an air conditioning system 200 that heats and cools a room. The air conditioning system 2000 comprises an outdoor unit 210 and an indoor unit 270. The outdoor unit 210 comprises a compressor 230, a four-way valve 240, an outdoor heat exchanger 250, an expansion valve (pressure reducing device) 260, and an outdoor unit control unit 100A.

[0082] The compressor 230 includes a discharge port 231 as a discharge section and an intake port 232 as an intake section. The compressor 230 is controlled by the outdoor unit control unit 100A to compress the refrigerant supplied from the intake port 232 through the intake pipe 233 and the four-way valve 240, and supplies the compressed refrigerant from the discharge port 231 to the four-way valve 240 through the discharge pipe 234.

[0083] The four-way valve 240 is connected to the discharge pipe 234 and the suction pipe 233, and is also connected to the outdoor heat exchanger 250 via the refrigerant piping 410 and to the indoor unit 270 via the refrigerant piping 420. The indoor unit 270 and the outdoor heat exchanger 250 are connected via the refrigerant piping 430. The four-way valve 240 is controlled by the outdoor unit control unit 100A to switch the air conditioning system 200 to either heating mode or cooling mode. When switched to cooling mode, the four-way valve 240 supplies refrigerant discharged from the compressor 230 to the outdoor heat exchanger 250 via the discharge pipe 234, and supplies refrigerant flowing out from the indoor unit 270 to the compressor 230 via the suction pipe 233. When switched to heating mode, the four-way valve 240 supplies refrigerant discharged from the compressor 230 to the indoor unit 270 via the discharge pipe 234, and supplies refrigerant flowing out from the outdoor heat exchanger 250 to the compressor 230 via the suction pipe 233.

[0084] The outdoor heat exchanger 250 is connected to the expansion valve 260 via a refrigerant pipe 430 upstream of the expansion valve 260. An outdoor fan F1 is located near the outdoor heat exchanger 250. The outdoor fan F1 is rotated by a first motor 1A to draw outside air into the outdoor unit 210 and releases the outside air, which has exchanged heat with the refrigerant by the outdoor heat exchanger 250, to the outside of the outdoor unit 210. In cooling mode, the outdoor heat exchanger 250 exchanges heat between the refrigerant supplied from the four-way valve 240 and the outside air drawn into the outdoor unit 210, and supplies the heat-exchanged refrigerant to the expansion valve 260. In heating mode, the outdoor heat exchanger 250 exchanges heat between the refrigerant supplied from the expansion valve 260 and the outside air drawn into the outdoor unit 210, and supplies the heat-exchanged refrigerant to the four-way valve 240.

[0085] The expansion valve 260 is connected to the indoor unit 270 via the refrigerant piping 430 downstream of the expansion valve 260. In cooling mode, the expansion valve 260 reduces the pressure of the refrigerant supplied from the outdoor heat exchanger 250 by adiabatically expanding it, supplying the low-temperature, low-pressure two-phase refrigerant to the indoor unit 270. In heating mode, the expansion valve 260 reduces the pressure of the refrigerant supplied from the indoor unit 270 by adiabatically expanding it, supplying the low-temperature, low-pressure two-phase refrigerant to the outdoor heat exchanger 250. Furthermore, the opening degree of the expansion valve 260 is adjusted by the outdoor unit control unit 100A, which adjusts the flow rate of refrigerant supplied from the indoor unit 270 to the outdoor heat exchanger 250 in heating mode, and adjusts the flow rate of refrigerant supplied from the outdoor heat exchanger 250 to the indoor unit 270 in cooling mode.

[0086] The indoor unit 270 includes an indoor heat exchanger 280, an indoor fan 150B (blower), and an indoor unit control unit 100B. The indoor fan 150B (blower) is positioned near the indoor heat exchanger 280 and is rotated by a second motor 1B to draw indoor air into the indoor unit 270 and release the indoor air, which has exchanged heat with the refrigerant in the indoor heat exchanger 280, back into the room.

[0087] The indoor heat exchanger 280 is connected to the four-way valve 240 via the refrigerant piping 420 and to the expansion valve 260 of the outdoor unit 210 via the refrigerant piping 430. When the air conditioning system 200 is switched to cooling mode, the indoor heat exchanger 270 functions as an evaporator and the outdoor heat exchanger 250 functions as a condenser. When the air conditioning system 200 is switched to heating mode, the indoor heat exchanger 270 functions as a condenser and the outdoor heat exchanger 250 functions as an evaporator. In other words, in cooling mode, the indoor heat exchanger 280 exchanges heat between the low-temperature, low-pressure two-phase refrigerant supplied from the expansion valve 260 and the indoor air taken into the indoor unit 270, releases the heat-exchanged indoor air into the room, and supplies the heat-exchanged refrigerant to the four-way valve 240. In heating mode, the indoor heat exchanger 270 exchanges heat between the refrigerant supplied from the four-way valve 240 and the indoor air taken into the indoor unit 270, releases the heat-exchanged indoor air into the room, and supplies the heat-exchanged refrigerant to the expansion valve 260.

[0088] Figure 9 is a cross-sectional view of the main part of the heat source side unit (outdoor unit 210) in a refrigeration cycle system (air conditioning system 200) equipped with the blower F (outdoor blower F1) of the present invention, viewed from the side. The first motor 1A corresponds to motor 1 in the blower F of the present invention. The first motor 1A has support legs 11 that protrude from the outer circumferential surface side of the resin casing 10 and are fixed to the support base 220 of the outdoor unit 210. In the airflow generated when the impeller 300 rotates, the motor 1A is positioned downstream of the outdoor heat exchanger 250. The impeller 300 is attached to the output end 61 (impeller fixing part) of the shaft 6 of the first motor 1A. The impeller 300 provided in the blower F1 in this embodiment is a propeller fan (axial flow fan). In this embodiment, the temperature sensor S is attached to the heat exchanger 250, for example. Of course, this is not the only option; it is sufficient if it is mounted in a location where a temperature equivalent to the ambient temperature of motor 1 can be measured.

[0089] In this embodiment, the propeller fan, which is the impeller 300 of the blower F (outdoor blower F1), has a mass of approximately 1.5 kg, and the radial load applied to the bearings (first bearing 7, second bearing 8) via the output end 61 (impeller fixing part) that supports the propeller fan is approximately 36 N. When the radial load applied to the bearings supporting the impeller 300 is large (for example, 10 N or more, especially 20 N or more), the lubricant film thickness in the motor 1 bearings (first bearing 7, second bearing 8) tends to be insufficient, and there is a problem that abnormal noise is likely to occur, especially when the motor 1 is driven at low speed. Therefore, in this embodiment, even when the motor 1 is driven at low speed while a large radial load is applied to the output end 61, by using urea grease G as the lubricant in the motor 1 bearings (7, 8), metal-to-metal contact within the bearings can be prevented, and the generation of abnormal noise in the bearings can be suppressed.

[0090] In this embodiment, the temperature sensor S may also be installed to detect the intermediate heat exchanger temperature (condensation temperature), which is the temperature of the intermediate part of the outdoor heat exchanger 250 (the intermediate position between the compressor 230 side and the expansion valve 260 side of the piping 250A of the outdoor heat exchanger 250). For example, the temperature sensor S is installed in the piping 250A of the outdoor heat exchanger 250 at a height position opposite the motor 1A in the axial direction of the motor 1A. When the temperature sensor S is installed to detect the intermediate heat exchanger temperature, the detected temperature may be considered as the ambient temperature of the motor. Alternatively, the ambient temperature of the motor may be calculated from the intermediate heat exchanger temperature based on the rotational speed of the compressor 230 and the motor 1A, etc.

[0091] In this embodiment, the case in which the air conditioner 200 is equipped with a temperature sensor S is illustrated, but the invention is not limited to this, and the air conditioner 200 does not need to be equipped with a temperature sensor. For example, the outdoor unit 210 of the air conditioner 200 itself may not be equipped with a temperature sensor, and when the ambient temperature of the motor 1 while it is operating in low-speed rotation mode is measured by an external temperature sensor provided separately from the outdoor unit 210, the ambient temperature t [°C] of the motor 1 may end up being high (30 ≤ t ≤ 40). In this case, it is sufficient that the motor 1 can rotate in low-speed rotation mode throughout the entire temperature range of the actual ambient temperature t [°C] of the motor 1, which is between 30°C and 40°C.

[0092] Furthermore, in this embodiment, the blower F (outdoor blower F1), in cooling mode, generates an airflow that passes through the outdoor heat exchanger 250 (condenser) as described above. The motor 1 is positioned downstream of the outdoor heat exchanger 250 (condenser) in the airflow that passes through the outdoor heat exchanger 250 (condenser). When the compressor 230 is driven and the airflow that has undergone heat exchange by the outdoor heat exchanger 250 (condenser) passes around the motor 1A, the motor 1A is driven in low-speed rotation mode. In other words, even if the ambient temperature of the motor 1A becomes high (for example, 40°C or higher) due to exposure to the air that has passed through the condenser (in cooling mode), causing the temperature of the lubricating oil in the bearing to rise, the kinematic viscosity to decrease, and the oil film thickness to decrease, using urea-based grease allows for the formation of an oxide film, which suppresses metal-to-metal contact within the bearing. As a result, even if the rotation speed of the motor 1A of the blower F is reduced to a low speed (for example, 150 rpm or less), abnormal wear in the bearing can be prevented.

[0093] In this embodiment, the motor 1 has been described as being used in a blower F1 (outdoor fan) mounted on the heat source side unit (outdoor unit 210) of the refrigeration cycle system (air conditioning system 200). However, it is not limited to this, and may also be used in an indoor blower F2 (indoor fan 150B) mounted on the user side unit (indoor unit 270) of the refrigeration cycle system (air conditioning system 200). Similarly, the motor 1 may be used in both the outdoor blower F1 (outdoor fan 150A) mounted on the heat source side unit (outdoor unit 210) and the indoor blower F2 (indoor fan 150B) mounted on the user side unit (indoor unit 270) of the refrigeration cycle system (air conditioning system 200). For example, when motor 1 is used in an outdoor blower F1 (outdoor fan 150A), the outdoor blower F1 generates an airflow that passes through the outdoor heat exchanger 250 as a condenser in cooling mode, and generates an airflow that passes through the outdoor heat exchanger 250 as an evaporator in heating mode. In this embodiment, the case in which the impeller 300 of the blower F (outdoor fan 150B) on which motor 1 is mounted is an axial flow fan (propeller fan, etc.) is illustrated, but of course, it is not limited to this, and the impeller 300 of the blower F on which motor 1 is mounted may be a centrifugal fan (sirocco fan, turbo fan, etc.) or a once-through fan (cross-flow fan, etc.). In addition, the outdoor unit of an air conditioner is illustrated as the heat source side unit of the refrigeration cycle system on which the outdoor blower F1 is mounted, but it is not limited to this, and the outdoor blower F1 may be mounted on a chiller unit (not shown). Furthermore, while the indoor unit of an air conditioning system was given as an example of the user-side unit of the refrigeration cycle system on which the indoor blower F2 is installed, the system is not limited to this, and the blower F1 may also be installed in a fan coil unit (not shown).

[0094] [Air purifier] In this embodiment, the blower F on which the motor 1 is mounted is described as an outdoor blower F1 mounted on the outdoor unit 210 of the air conditioner 200, but it is not limited to this and may also be used in an air purifier. Figure 10 is a cross-sectional view taken longitudinally from the center of an air purifier 500 on which the blower F is mounted.

[0095] As shown in Figure 10, the inside of the air purifier 500 housing has an air passage 510 that guides the air introduced from the air intake port 511 to the air outlet port 512. A blower F3 is provided in the middle of this air passage 510 to circulate the air in the air passage 510 from the air intake port 511 to the air outlet port 512. The blower 150C of the blower F3 is configured as a sirocco fan 1C' equipped with a motor 1C. It is preferable to use a centrifugal fan, a sirocco fan 1C', for the impeller 300 of this blower 150C, but of course it is not limited to this, and any fan that has the function of circulating air is acceptable. For example, an axial flow fan, a once-through fan, or other type of fan may be used as the impeller 300.

[0096] Furthermore, a pre-filter 520, a dust collection filter 521, a deodorizing unit 530, a unit guide 531, and a humidifying unit 540 are arranged in the air passage 510 between the air intake 511 and the blower 150C. In addition, an ozonizer 550 that generates ozone to sterilize and deodorize the air is arranged in the air passage 510 between the blower 150C and the air outlet 512.

[0097] In other words, by rotating the impeller 300, air is drawn into the air purifier 500 from its surroundings, and dust and other particles in the air are removed by the filters (pre-filter 520, dust collection filter 521) before being discharged into the surroundings. At this time, the blower F3, by configuring the motor 1C that drives the blower (fan) 150C as described above, can operate the air purifier 500 continuously for a long time even when the blower (fan) 150C is rotating at a low speed, and even when the ambient temperature around the motor 1C is high.

[0098] Furthermore, the temperature sensor S mentioned above only needs to be able to measure a temperature equivalent to the ambient air temperature around the motor 1C. For example, it can be installed near the air outlet of the air purifier 500, but the location of the temperature sensor S is not limited to this. Also, it is not limited to cases where the air purifier 500 is equipped with a temperature sensor. For example, the air purifier 500 itself does not have a temperature sensor S, and when the ambient temperature of the motor 1C while it is operating in low-speed rotation mode is measured by an external temperature sensor provided separately from the air purifier 500, the ambient temperature t [°C] of the motor 1C may end up being high (30 ≤ t ≤ 40). In this case, it is sufficient that the motor 1C can rotate in low-speed rotation mode throughout the entire temperature range of the actual ambient temperature t [°C] of the motor 1C, from 30°C to 40°C.

[0099] In this embodiment, the blower F on which the motor 1 is mounted has been described as a blower F1 mounted on the heat source side unit (outdoor unit 210 of the air conditioner) of the refrigeration cycle unit (air conditioner 200), but it is of course not limited to this and may also be used in the ventilation unit 600. Figure 11 is a conceptual diagram showing the ventilation unit 600 on which the blower F is mounted.

[0100] As shown in Figure 11, the ventilation unit 600 includes a casing 610 that houses a total heat exchanger 620. The casing 610 is provided with an outdoor air supply port 611, an indoor air supply port 612, an indoor exhaust port 613, and an outdoor exhaust port 614. In addition, an air supply passage 621 and an exhaust passage 622 are formed in the internal space of the casing 610. The air supply passage 621 has the outdoor air supply port 611 connected to one end and the indoor air supply port 612 connected to the other end. The exhaust passage 622 has the indoor exhaust port 613 connected to one end and the outdoor exhaust port 614 connected to the other end.

[0101] The total heat exchanger 620 may be a rotary total heat exchanger or a stationary total heat exchanger. The total heat exchanger 620 is accessed through both the supply air passage 621 and the exhaust air passage 622. In other words, the supply air passage 621 passes through one of the passages of the total heat exchanger 620, and the exhaust air passage 620 passes through the other passage of the total heat exchanger 622. In other words, the total heat exchanger 620 is located in the middle of both the supply air passage 621 and the exhaust air passage 622.

[0102] In the ventilation unit 600, outdoor air flows into the room through the supply passage 621, and indoor air flows outwards through the exhaust passage 622. The indoor air flowing through the supply passage 621 and the indoor air flowing through the exhaust passage 622 exchange sensible heat and latent heat in the total heat exchanger 620. As a result, total heat exchange takes place between the air flowing through the supply passage 621 and the air flowing through the exhaust passage 622.

[0103] The ventilation unit 600 further comprises a supply fan 150d (blower) and an exhaust fan 150e (blower). The supply fan 150d is located downstream of the total heat exchanger 620 in the supply passage 621 (i.e., on the indoor side supply air inlet 612 side). The exhaust fan 150e is located downstream of the total heat exchanger 620 in the exhaust passage 622 (i.e., on the outdoor side exhaust outlet 614 side).

[0104] The ventilation unit 600 includes a control unit 630. The control unit 630 is electrically connected to the motor 1d of the supply fan 150d and the motor 1e of the exhaust fan 150e, and controls the rotational speed of each motor (1d, 1e). The control unit 630 may be located inside or outside the ventilation unit, as long as it is configured to control the rotational speed of the motors (1d, 1e). Furthermore, the control unit 630 may be divided into two control units, each controlling motor 1d and motor 1e individually.

[0105] The ventilation unit 600 shown in Figure 11 expels indoor air to the outside by rotating the impeller 300 of the exhaust fan 150e (blower) of the blower F4. By configuring the motor 1e that drives the exhaust fan 150e (blower) as described above, the ventilation unit 600 equipped with the blower F4 can be operated continuously for a long period of time even when the exhaust fan 150e is rotating at a low speed, and even when the ambient temperature of the motor 1e is high. Here, we have exemplified the case where urea grease is used for the motor 1e of the exhaust fan 150e and the control unit 630 rotates the motor 1e continuously at a low speed for a long period of time. However, urea grease may also be used for the motor 1d of the supply fan 150d, and the control unit 630 may rotate the motor 1d continuously at a low speed for a long period of time even when the ambient temperature of the motor 1d is high.

[0106] Furthermore, although this explanation uses a ventilation unit 600 equipped with a heat exchanger (total heat exchanger 620) as an example, a ventilation unit without a heat exchanger may also be used. Also, although this explanation uses a ventilation unit having both a supply air passage 621 and an exhaust air passage 622 as an example, a ventilation unit having only one of either the supply air passage 621 or the exhaust air passage 622 may also be used.

[0107] Furthermore, the temperature sensor S mentioned above only needs to be able to measure a temperature equivalent to the ambient air temperature around the motor 1e. For example, it can be installed near the intake of the ventilation unit 600, but the location where the temperature sensor is installed is not limited to this. Also, it is not limited to the case where the ventilation unit 600 is equipped with a temperature sensor. For example, the ventilation unit 600 itself does not have a temperature sensor, and when the ambient temperature of the motor 1e is measured with an external temperature sensor while it is operating in low-speed rotation mode, the ambient temperature t [°C] of the motor 1e may end up being high (30 ≤ t ≤ 40). In this case, it is sufficient that the motor 1e can rotate in low-speed rotation mode throughout the entire temperature range of the actual ambient temperature t [°C] of the motor 1e, from 30°C to 40°C.

[0108] In this embodiment, the blower F on which the motor 1 is mounted has been described as a blower F1 mounted on the heat source side unit (outdoor unit 210 of the air conditioner) of the refrigeration cycle system (air conditioner 200), but it is not limited to this and may be used in a refrigeration cycle system (air conditioner 200') that performs reheat dehumidification. Figure 12 is a conceptual diagram showing a refrigeration cycle system (air conditioner 200') that performs reheat dehumidification and is equipped with a blower F1'. Further explanations similar to those for the refrigeration cycle system (air conditioner 200) described above will be simplified or omitted.

[0109] The air conditioning system 200' comprises an outdoor unit 210' and an indoor unit 270'. The outdoor unit 210' comprises a compressor 230', an outdoor heat exchanger 250', an expansion valve (pressure reducing device) 260', and an outdoor blower F1'.

[0110] The compressor 230 compresses the refrigerant supplied from the indoor unit 270' via the refrigerant piping 420', and supplies the compressed refrigerant to the outdoor heat exchanger 250' via the refrigerant piping 410.

[0111] The indoor unit 270' and the outdoor heat exchanger 250' are connected via refrigerant piping 430'.

[0112] The outdoor heat exchanger 250' is connected to the expansion valve 260' via the refrigerant piping 430'. An outdoor fan F5 is located near the outdoor heat exchanger 250'. The outdoor fan F5 is rotated by the first motor 1A' described above, drawing outside air into the outdoor unit 210' and releasing the outside air, which has exchanged heat with the refrigerant by the outdoor heat exchanger 250', to the outside of the outdoor unit 210'. In the case of reheat dehumidification operation, the outdoor heat exchanger 250' functions as a condenser that exchanges heat between the refrigerant supplied from the indoor unit 270' and the outside air drawn into the outdoor unit 210', and supplies the heat-exchanged refrigerant to the expansion valve 260'.

[0113] The expansion valve 260' is connected to the indoor unit 270' via the refrigerant piping 430'. The expansion valve 260' is fully open during outdoor heat dehumidification operation. The refrigerant that has exchanged heat with the outside air in the outdoor heat exchanger 250' passes through the fully open expansion valve 260' and flows into the indoor heat exchanger 280'.

[0114] The indoor unit 270' includes an indoor heat exchanger 280', an indoor fan 150B' (blower), and a solenoid valve B. The indoor fan 150B' (blower) is positioned near the indoor heat exchanger 280' and is rotated by a second motor 1B' to draw indoor air into the indoor unit 270' and release the indoor air, which has exchanged heat with the refrigerant in the indoor heat exchanger 280', into the room.

[0115] Solenoid valve B functions as an expansion valve. Solenoid valve B is connected between the indoor first heat exchanger 280A (described later) and the indoor second heat exchanger (described later).

[0116] The indoor heat exchanger 280 is connected to the compressor 230' via refrigerant piping 420' and to the expansion valve 260' of the outdoor unit 210' via refrigerant piping 430'. The indoor heat exchanger 280' has an indoor first heat exchanger 280A and an indoor second heat exchanger. The indoor first heat exchanger 280A is connected to the expansion valve 260'. The indoor second heat exchanger 280B is connected to the compressor 230'.

[0117] In reheat dehumidification operation, the outdoor heat exchanger 250' and the indoor first heat exchanger 280A function as condensers, while the indoor second heat exchanger 280B functions as an evaporator. In other words, the indoor air is heated in the indoor first heat exchanger 280A, and the indoor air is dehumidified and cooled in the indoor second heat exchanger 280B. As a result, in reheat dehumidification operation, the indoor humidity decreases while the decrease in indoor air temperature is suppressed.

[0118] Conventionally, when the outside temperature was relatively high, requiring reheat dehumidification, it was not possible to maintain the rotation speed of the outdoor fan in low-speed mode (due to insufficient oil film in the bearings), and intermittent operation involving repeated switching between low-speed and stopped operation was necessary. As a result, there was a problem in that the latent heat capacity decreased while the fan was stopped, leading to a reduction in dehumidification volume. In this embodiment, it is possible to continuously maintain operation in low-speed mode even during reheat dehumidification, and the amount of dehumidification can be improved compared to when operation in low-speed mode is performed intermittently.

[0119] Furthermore, in this embodiment, the motor 1 is not limited to the examples described above and may be used for a variety of applications. For example, it may be used in a bathroom heater.

[0120] In other words, in bathroom heating, warm air can be provided into the bathroom by rotating the impeller 300 of the blower F toward the bathroom through the piping that circulates the heated water. At that time, by configuring the motor 1 that drives the fan as described above, the motor 1 of the blower F's fan 150 can operate continuously for a long time at a low speed even when the ambient temperature is high. [Explanation of Symbols]

[0121] 1…motor 2...Stator 3…Rotor 4…Bracket 5…Circuit board 6…Shaft 61…Output end (impeller fixing part) 7…First bearing 8…Second bearing 10… Resin outer shell 71…Outer ring 72...Inner circle 73...Cage 74... Rolling element 100... Control Unit 150... Blower (fan) 200... Air conditioning system (refrigeration cycle system) 210...Outdoor unit (heat source side unit) 270... Indoor unit (user-side unit) 300... Impeller F…Blower device G... Grease W...bearing space

Claims

1. A motor having a stator, a rotor positioned inside the stator, a shaft to which the rotor is fixed, and a bearing that rotatably supports the shaft, and having a variable rotational speed, A blower comprising a control unit for controlling the rotational speed of the motor, The control unit has at least one rotation mode in which the rotation speed n [rpm] of the motor satisfies the condition 50 ≤ n < 150. The bearing comprises an inner ring, an outer ring, a plurality of rolling elements provided in an annular bearing space formed between the inner ring and the outer ring, and urea-based grease filled in the bearing space. The motor is capable of rotating in the rotation mode when the ambient temperature t [°C] of the motor satisfies at least 30 ≤ t ≤ 40. Blower.

2. A blower according to claim 1, At least one surface of the inner ring, outer ring, and rolling element of the bearing is formed with an oxide film of carboxylic acid, which is produced by the oxidation of urea groups contained in the urea-based grease. Blower.

3. A blower according to claim 1, The urea-based grease comprises a base oil, an additive, and a thickener, the thickener comprising a urea group. The base oil has a kinematic viscosity ν of 40 [mm² / s] or more at 40°C. Blower.

4. A blower according to claim 1, The motor is capable of rotating in the rotation mode when the ambient temperature t [°C] of the motor satisfies at least 25 ≤ T ≤ 45. Blower.

5. A blower according to claim 1, In the aforementioned rotation mode, the lower limit rotational speed nmin [rpm] of the motor is 50 ≤ nmin < 100. Blower.

6. The blower according to claim 1, A refrigerant circuit is formed by sequentially connecting a compressor, condenser, pressure reducing device, and evaporator via refrigerant piping. Equipped with, The blower generates an airflow that passes through the condenser or the evaporator. Refrigeration cycle equipment

7. A refrigeration cycle apparatus according to claim 6, The blower generates an airflow that passes through the condenser. The motor is positioned downstream of the condenser in the flow of the airflow passing through the condenser. The motor is driven in the rotational mode when the airflow that has undergone heat exchange by the condenser is passing around the motor. Refrigeration cycle device.

8. A refrigeration cycle apparatus according to claim 7, The motor is driven in the rotation mode when the intermediate temperature of the heat exchanger in the condenser is 40°C or higher. Refrigeration cycle device.

9. A refrigeration cycle apparatus according to claim 6, The aforementioned refrigeration cycle device is an air conditioning system having an outdoor unit and an indoor unit. The outdoor unit comprises an outdoor heat exchanger, a compressor, and an outdoor blower. The indoor unit comprises an indoor first heat exchanger, an indoor second heat exchanger, and an indoor blower. The control unit causes the outdoor heat exchanger and the indoor first heat exchanger to function as the condenser, and the indoor second heat exchanger to function as the evaporator, during the reheat dehumidification operation of the air conditioning system. Refrigeration cycle device.

10. A ventilation unit comprising the blower device described in claim 1.

11. An air purifier comprising the blower device described in claim 1.

Images