Air supply device, heat source-side unit of refrigeration cycle device provided with the air supply device, utilization-side unit of refrigeration cycle device, refrigeration cycle device, ventilation unit, and air purifier

Abstract

The present application provides a kind of air supply device that can prevent oil film formation in the bearing from being poor even at low speed rotation and can be continuously operated for a long time, and heat source side unit, utilization side unit, refrigeration cycle device, ventilation unit and air purifier with the air supply device.The air supply device related to one mode of the present application is provided with: motor, which has stator, rotor arranged inside stator, shaft fixed with rotor, and bearing rotatably supporting the shaft, and the rotational speed of motor can be changed;And control part controls the rotational speed of motor.Control part at least has the rotational speed n [rpm] of motor is set to the rotational speed that satisfies 50≤n <100 of rotation mode.The bearing has inner ring, outer ring, multiple rolling elements arranged in the annular bearing space formed between inner ring and outer ring, and urea-based lubricating grease filled in the bearing space.The air supply device can maintain the motor for more than 5 hours in rotation mode.

Description

Technical Field

[0001] The present invention relates to an air supply device and a heat source side unit of a refrigeration cycle device having the air supply device, a utilization side unit of the refrigeration cycle device, a refrigeration cycle device, an air exchange unit, and an air purifier. Background Technology

[0002] Air supply devices that use an electric motor to rotate an impeller are known. For example, Patent Document 1 describes an air supply device comprising: an electric motor with a variable rotation speed, the rotating shaft of which is supported by a bearing sealed with lubricant; and a control unit that drives the electric motor, wherein if the electric motor is continuously driven at 50 rpm or more and less than 300 rpm for 10 minutes or more and less than 5 hours, the control unit drives the electric motor at 300 rpm or more for 1 second or more and less than 2 minutes.

[0003] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2022-117021 Summary of the Invention

[0004] The technical problem that the invention aims to solve In recent years, there has been a demand for air supply devices that can prevent poor oil film formation in bearings even at low rotation speeds and can operate continuously for extended periods. However, in Patent Document 1, if the low rotation speed is maintained for a long time, poor oil film formation occurs in the bearing. Therefore, it is necessary to switch to a high rotation speed to form an oil film in the bearing, but there is a problem that it is difficult to make the air supply device operate continuously at low speeds for extended periods.

[0005] In view of the above, the object of the present invention is to provide an air supply device that can prevent poor oil film formation in the bearing even at low speeds and can operate continuously for a long time, as well as a heat source side unit of a refrigeration cycle device equipped with the air supply device, a utilization side unit of the refrigeration cycle device, a refrigeration cycle device, an air exchange unit, and an air purifier.

[0006] Technical solutions for solving technical problems To achieve the above objectives, one aspect of the present invention relates to an air supply device comprising: an electric motor with variable speed, having a stator, a rotor disposed inside the stator, a shaft fixed to the rotor, and a bearing that rotatably supports the shaft, and the speed of the electric motor being changeable; and a control unit that controls the speed of the electric motor.

[0007] The control unit described above has at least a rotation mode that sets the rotational speed n [rpm] of the motor to a speed that satisfies 50 ≤ n < 100.

[0008] The aforementioned bearing has an inner ring, an outer ring, a plurality of rolling elements disposed within an annular bearing space, and a urea-based grease filled within the bearing space, wherein the bearing space is formed between the inner ring and the outer ring. The aforementioned air supply device enables the aforementioned motor to maintain the aforementioned rotation mode for a period of time longer than 5 hours.

[0009] According to the aforementioned air supply device, the aforementioned control unit has at least a rotation mode that sets the rotational speed n [rpm] of the aforementioned motor to a speed satisfying 50 ≤ n < 100. The aforementioned bearing has an inner ring, an outer ring, a plurality of rolling elements disposed within an annular bearing space formed between the inner ring and the outer ring, and a urea-based grease filled within the aforementioned bearing space. That is, by using urea-based grease in the bearing, even when operating at a low speed of 50 ≤ n < 100 for a period of more than 5 hours, the abnormal noise generated by the low-speed rotation of the bearing can be suppressed.

[0010] The aforementioned air supply device can also maintain the aforementioned rotation mode for a longer period of time than 24 hours.

[0011] In the above-mentioned rotating mode, the rotational speed n [rpm] of the above motor can also satisfy 50 ≤ n < 80.

[0012] The aforementioned urea-based grease may contain a base oil, additives, and a thickener, wherein the thickener contains urea groups, and the base oil has a kinematic viscosity ν of 40 mm at 40°C. 2 [s] Above.

[0013] The kinematic viscosity ν of the above-mentioned base oil at 40℃ can be 80 [mm]. 2 [s] Above.

[0014] Alternatively, the motor may also have an impeller mounting portion on one end of the shaft for mounting the impeller.

[0015] The radial load applied to the aforementioned bearing can be 10N or more.

[0016] It can also be the heat source side unit of a refrigeration cycle device equipped with the aforementioned air supply device.

[0017] It can also be a utilization unit of a refrigeration cycle device equipped with the aforementioned air supply device.

[0018] It can also be a refrigeration cycle device having at least one of the above-mentioned heat source side unit and the above-mentioned utilization side unit.

[0019] It can also be an air exchange unit equipped with the aforementioned air supply device.

[0020] It can also be an air purifier equipped with the aforementioned air supply device.

[0021] Invention Effects According to the present invention, it is possible to provide an air supply device that can prevent poor oil film formation in the bearing even at low speeds and can operate continuously for a long time, as well as a heat source side unit of a refrigeration cycle device equipped with the air supply device, a utilization side unit of the refrigeration cycle device, a refrigeration cycle device, an air exchange unit, and an air purifier. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of the electric motor of the air supply device according to an embodiment of the present invention.

[0023] Figure 2 This is a diagram showing the bearings of the aforementioned electric motor.

[0024] Figure 3 This is a block diagram of the motor and control unit of the aforementioned air supply device.

[0025] Figure 4 The diagrams illustrate the phenomenon of abnormal noise generated from the aforementioned bearings. (A) shows the situation where the rolling elements rotate at high speed, and (B) shows the situation where the rolling elements rotate at low speed.

[0026] Figure 5 This is a diagram illustrating the abnormal noise caused by changes in the rotational speed of the aforementioned motor.

[0027] Figure 6 The diagram shows the relationship between the bearing and the grease. (A) represents before rotation, and (B) represents during rotation.

[0028] Figure 7 This is a graph showing the relationship between the friction coefficient and lubrication condition of the aforementioned bearings.

[0029] Figure 8 This is a conceptual diagram showing a refrigeration cycle device (air conditioning device) equipped with the air supply device of the present invention.

[0030] Figure 9 This is a cross-sectional view of the main part of the heat source side unit (outdoor unit) of the refrigeration cycle device (air conditioning device) equipped with the air supply device of the present invention, viewed from the side.

[0031] Figure 10 This is a cross-sectional view of an air purifier equipped with the air supply device of the present invention.

[0032] Figure 11 This is a conceptual diagram showing an air exchange unit equipped with the air supply device of the present invention. Detailed Implementation

[0033] Next, embodiments of the present invention will be described with reference to the accompanying drawings. In the following drawings, the same or similar parts are labeled with the same or similar symbols. 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.

[0034] Furthermore, the embodiments shown below illustrate apparatus and methods for embodying the technical concept of the present invention. The technical concept of the present invention does not limit the shape, structure, or arrangement of the constituent components to the following. Various modifications can be made to the technical concept of the present invention within the scope of the claims as defined in the claims.

[0035] Hereinafter, an air supply device F according to one embodiment of the present invention will be described.

[0036] Figure 1 This is a cross-sectional view of the motor 1 of the air supply device F according to an embodiment of the present invention. Figure 2 This is a diagram showing the bearings (first bearing 7, second bearing 8) of the electric motor 1. Furthermore, Figure 3 This is a block diagram of the motor 1 and control unit 100 of the air supply device F. (See diagram below.) Figure 1 As shown, the motor 1 is, for example, a brushless DC motor. In this embodiment, the motor 1 is used, for example, to drive the rotation of the impeller 300 of the air supply device F mounted on the refrigeration cycle device, particularly on the heat source side unit (e.g., the outdoor unit 210 of the air conditioning unit 200 described later).

[0037] like Figure 3 As shown, the air supply device F has a control unit 100 and an air supply fan 150. The air supply fan 150 has an electric motor 1 and an impeller 300 driven by the electric motor 1.

[0038] (Electric motor and air supply device) The motor 1 is a variable frequency motor with variable speed, which includes a stator 2, a rotor 3, a shaft 6, bearings (first bearing 7, second bearing 8), a bracket 4, a resin outer contour 10, and a circuit board 5.

[0039] (Rotor) The rotor 3 has an annular permanent magnet portion 31 and a rotor body 30. The rotor body 30 has an outer peripheral surface and an inner peripheral surface. The permanent magnet portion 31 is fixed to the outer peripheral surface of the rotor body 30. The rotating shaft 6 is fixed to the inner peripheral surface of the rotor body. Thus, the rotating shaft 6 and the rotor body 30 are driven to rotate integrally.

[0040] The rotor 3 is a surface magnet type in which a permanent magnet portion 31 is fixed in a ring on the outer peripheral surface. The permanent magnet portion 31 is formed in a ring by multiple (e.g., 8 or 10) permanent magnets, with N poles and S poles alternating at equal intervals in the circumferential direction. In addition, the permanent magnet portion 31 is typically formed of a sintered metal body such as an Nd-Fe-B alloy, but plastic magnets formed by fixing magnet powder with resin can also be used.

[0041] (stator) The stator 2 comprises: a stator core 21 having a cylindrical yoke and a plurality of teeth extending from the yoke toward the inner diameter side; and a winding (coil) 22 wound around the teeth. The stator core 21 is, for example, a laminate containing multiple sheets of soft magnetic material such as electromagnet steel plates. The outer peripheral surface of the stator 2 (stator core 21) is covered by a resin outer contour 10 (see reference). Figure 1 The stator 2 is arranged such that the permanent magnet part 31 of the rotor 3 is radially separated from the stator core 21 of the stator 2 by a gap (magnetic gap).

[0042] (Resin outer contour) The resin outer contour 10 is formed of an insulating resin material. For example... Figure 1 As shown, it is formed as a hollow cylinder with an open end 10A at one end of the shaft 6 in the axial direction C (in this embodiment, the side opposite to the output end 61 of the shaft 6). Here, the output end 61 refers to the end of the shaft 6 located on the load side (the side connected to the load) of the motor 1, which functions as an impeller fixing part for mounting the impeller 300, which will be described later. As described above, the resin outer contour 10 is integrally formed with the stator 2. The resin material forming the resin outer contour 10 is not particularly limited, and for example, it is formed from BMC (Bulk Molding Compound: unsaturated polyester resin).

[0043] Furthermore, the resin outer contour 10 has a mounting surface 9. The mounting surface 9 is formed on the inner circumferential surface of the resin outer contour 10, and is an inner circumferential plane perpendicular to the axial direction. It is disposed on the opposite side of the output end 61 of the rotating shaft 6, spaced apart from the rotor 3 in the axial direction. The mounting surface 9 supports the circuit board 5, which will be described later. The mounting surface 9 can be formed continuously in the circumferential direction on the inner circumferential surface of the resin outer contour 10, or it can be formed at multiple points spaced apart along its circumferential direction.

[0044] The resin outer contour 10 also has a second bearing housing portion 10C for housing the 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 blocked around the axis C. The second bearing housing portion 10C is located at the bottom 10B of the resin outer contour 10 on the side opposite to the opening end 10A.

[0045] (Circuit board) The circuit board 5 includes a wiring board and electronic components that generate heat when energized, mounted on the surface of the wiring board (the surface opposite to the output end 61 of the rotation shaft 6). The circuit board 5 is generally circular in shape, and its periphery is supported on the mounting surface 9, for example, by bonding, adhesive, threading, welding, etc.

[0046] Electronic components that generate heat when powered are mainly semiconductor components such as power supply ICs and ICs for controlling the drive current of motors, but may also include passive components such as capacitors. In addition to the electronic components, the wiring board also mounts other components, such as connectors that connect to the power cable, but these are not shown in the diagram. The power cable is connected to a power source (not shown) through a cable insertion portion formed near the open end 10A of the resin outer contour 10, extending within a predetermined circumferential angle range.

[0047] (Staff) The bracket 4 has a first bearing housing portion 41 and a circular plate portion 42. The radiator 4 is mounted and fixed to the open end 10A of the resin outer contour 10. The radiator 4 is formed of a metal material with excellent thermal conductivity, such as aluminum. The radiator 4 is formed, for example, by die casting.

[0048] The radiator 4 functions as a cover member (support) that closes the opening of the resin outer contour 10 by covering the opening end 10A of the resin outer contour 10. The radiator 4 is fixed to the opening end 10A of the resin outer contour 10 using a plurality of threaded members (not shown).

[0049] (Bearing) like Figure 2 As shown, 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.

[0050] like Figure 2 As shown, 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. Multiple rolling elements 74 of the first bearing 7 are disposed in the bearing space W1, which is an annular space formed between the inner ring 72 and the outer ring 71. A retainer 73 is disposed within the bearing space W1 to hold the rolling elements 74 in a rolling position. The retainer 73 holds the multiple rolling elements 74 at constant intervals in the circumferential direction of the first bearing 7. Grease G is a semi-solid lubricant containing base oil, additives, and thickeners, and is filled within the bearing space W1.

[0051] The outer ring 81 of the second bearing 8 is formed in an annular shape and fixed to the resin outer contour 10 (second bearing housing 10C). The inner ring 82 of the second bearing 8 is fixed to the output end 61 of the rotating shaft 6. Furthermore, a plurality of rolling elements 84 of the second bearing 8 are disposed within the annular space formed between the inner ring 82 and the outer ring 81, i.e., the bearing space W2. A retainer 83 is disposed within the bearing space W2 to retain the rolling elements 84 for free rolling. Furthermore, the retainer 83 holds the plurality of rolling elements 84 at certain intervals in the circumferential direction of the second bearing 8. The grease G is a semi-solid lubricant containing base oil, additives, and thickeners, and is filled within the bearing space W2. In this embodiment, the grease G is a urea grease.

[0052] The grease G functions as a lubricant by using shear force to fluidize the base oil through external pressure. Specifically, as the rolling element 74 rotates, pressure is applied to the grease G, causing the base oil to seep out and form an oil film between the outer rings 71 and 81, the inner rings 72 and 82, and the rolling element 74. This allows the rolling element 74 to rotate smoothly.

[0053] The urea grease used in the example grease G refers to a grease containing a urea compound with an intramolecular urea group (-NHCONH-) as a thickener. The urea compound used as a thickener is preferably a diurea having two intramolecular urea groups, but compounds with three or more urea groups (e.g., triurea, tetraurea) can also be used. Furthermore, in this example, aliphatic diurea is used as the diurea, but aromatic diurea can also be used. The urea grease is characterized by the fact that, since the thickener does not contain a metal group, it does not suffer from degradation due to oxidation of the base oil, and it has a long service life even at high temperatures.

[0054] The urea grease in the examples contains 5% to 30% by weight of a urea compound and 95% to 70% by weight of a base oil relative to the total amount of grease, but is not limited thereto. As an example of a method for manufacturing a urea compound, a method for obtaining diurea by reacting a diisocyanate compound, which is also a raw material for polyurethane, with an amine compound is known.

[0055] The rotating shaft 6 is supported by the first bearing 7 and the second bearing 8 so that it can rotate about the axis C with respect to the bracket 4 and the resin outer contour 10.

[0056] Furthermore, in this embodiment, the lubricating grease G comprises either a first urea grease G1 or a second urea grease G2 as a urea grease. The base oil of the first urea grease G1 has synthetic hydrocarbons as its main component, and the kinematic viscosity ν of this base oil at 40°C is 48 [mm]. 2 / s], the thickener is a urea grease containing urea compounds. Furthermore, the main component of the base oil for the second urea grease G2 is ester oil, and this base oil has a kinematic viscosity ν of 100 [mm] at 40°C. 2 / s], the thickener is a urea grease containing urea compounds.

[0057] like Figure 1 and the following Figure 9 As shown, the impeller 300A is fixed to the output end 61 (impeller fixing part) of the shaft 6 and rotates synchronously with the rotating shaft 6.

[0058] (Control Department) The control unit 100 includes a computer with a processor such as a CPU and storage devices such as ROM (Read Only Memory) and RAM (Random Access Memory). 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 to the motor 1 via a signal line to control the frequency of the pulse voltage. That is, the control unit 100 can control the rotational speed of the motor 1 using the control signal.

[0059] 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 through the low-speed rotation mode or the high-speed rotation mode.

[0060] The low-speed rotation mode sets the rotation speed n [rpm] of motor 1 to a speed that satisfies 50≤n<100, while the high-speed rotation mode sets the rotation speed n [rpm] of motor 1 to a speed that satisfies 100≤n.

[0061] That is, the control unit 100 rotates the motor 1 in a low-speed mode by rotating the motor 1 at a rotational speed n [rpm] where 50 ≤ n < 100. In addition, the control unit 100 rotates the motor 1 in a high-speed mode by rotating the motor 1 at a rotational speed n [rpm] where 100 ≤ n.

[0062] Here, Figure 4 The diagrams illustrate the phenomenon of abnormal noise generated from the bearing (first bearing 7). (A) shows the situation where the rolling element 74 rotates at high speed, and (B) shows the situation where the rolling element 74 rotates at low speed. Figure 4 The arrows shown indicate the direction of rotation of the rolling element.

[0063] like Figure 4As shown, the grease G is forced to exude base oil by pressure applied by the rotating rolling element 74. Figure 4 As shown in (A), the pressure applied to the grease G is high during high-speed rotation (speed n [rpm] is 100≤n). Therefore, the rolling element 74 can rotate smoothly by forming a sufficiently thick oil film between the rolling element 74 and the outer ring 71 through the base oil seeping from the grease G.

[0064] On the other hand, such as Figure 4 As shown in (B), at low speeds (rpm 50 ≤ n < 100), the pressure applied to the grease G is low. Therefore, less base oil seeps out of the grease G, resulting in an insufficient oil film thickness to form between the rolling element 74 and the outer ring 71, leading to oil film rupture. That is, under prolonged continuous low-speed rotation, maintaining a ruptured oil film (metal-to-metal contact) between the rolling element 74 and the outer ring 71 for an extended period may cause abnormal noise and bearing damage.

[0065] In use Figure 4 The above description explains the relationship between the rolling element 74 and the outer ring 71, but it is not limited to this; the same problem can occur even between the rolling element 74 and the inner ring 72. Furthermore, the same problem occurs not only with the first bearing 7, but also with the second bearing 8.

[0066] Here, Figure 5 This diagram shows whether any 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. Furthermore, Figure 6 This diagram shows the internal condition of bearing 7 when using grease G, which is a urea-based lubricant. Figure 6 (A) is a diagram representing the state before rotation. Figure 6 (B) is a diagram representing the state during rotation. Figure 7 This is a graph showing the relationship between the bearing's coefficient of friction and the lubrication condition.

[0067] Figure 5 The lithium-based grease shown 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; specifically, it refers to a lithium soap grease that uses lithium soap as a thickener. Specifically, the lithium soap grease used as a comparative example uses an ester oil as the main component of its base oil, which has a kinematic viscosity ν of 26 [mm] at 40°C. 2 Lithium soap grease [s].

[0068] exist Figure 5 In the middle, a vibration and noise analysis system (manufacturer: Bruel & Kjar, software: PULS, front end: using Type 3160-A-042) was used to measure the vibration and noise using the method described later. Figure 9The noise level of the blower F when the motor 1 is rotating is shown. Here, the impeller 300 (propeller fan) has a mass of approximately 1.5 kg, and is applied to... Figure 1 The axial loads on bearings 7 and 8 are both approximately 41 [N], the radial load applied to bearing 7 is approximately 21 [N], and the radial load applied to bearing 8 is approximately 36 [N]. The vertical axis represents the noise OA (overall) value [dB(A)], and the horizontal axis represents the time [h] during which motor 1 rotates continuously. Furthermore, Figure 5 The lithium-based grease in the diagram represents the case where the aforementioned lithium grease was used as the lubricant, and experiments were conducted with the continuous rotation speed fixed at 150 rpm. Similarly, the urea-based grease in the diagram represents the case where the aforementioned second urea grease was used as the lubricant, and experiments were conducted with the continuous rotation speeds fixed at 150 rpm, 100 rpm, and 50 rpm, respectively. Furthermore, Table 1 below shows whether the sound quality deteriorated after 10,000 hours of continuous rotation for both the motor using lithium grease and the motor using the second urea grease, and the continuous rotation speed of the motor at that time. In Table 1, "×" indicates that sound quality deteriorated under this condition (increased noise), and "○" indicates that sound quality did not deteriorate under this condition (no increase in noise).

[0069] [Table 1]

[0070] like Figure 5 As shown in Table 1, in lithium-based greases, when continuously rotating at 150 rpm, the noise OA value gradually increases from around 1000 h, increasing by approximately 6 dB(A) at 2200 h (sound deterioration). On the other hand, in the second urea grease, even after continuous operation for 10000 h at any of the following speeds (200 rpm, 150 rpm, 100 rpm, 50 rpm), no increase in noise OA value (sound deterioration) with increasing continuous rotation time was observed as in lithium-based greases.

[0071] Here, the investigation appears Figure 5The reason for the results in Table 1 is as follows. The parameter Λ is a measure of the degree of metal-to-metal contact, calculated by Λ = oil film thickness (e.g., the thickness of the oil film formed between the outer ring 71 and the rolling element 74) [mm] ÷ surface roughness (e.g., the surface roughness of the outer ring 71 or the rolling element 74) [mm]. Generally, when Λ < 1, it is considered boundary lubrication (a lubrication state in which local metal-to-metal contact occurs). Furthermore, when 1 < Λ < 3, it is considered mixed lubrication (a state in which boundary lubrication and fluid lubrication coexist). Moreover, when 3 < Λ, it is considered fluid lubrication (a lubrication state in which the two surfaces (e.g., the outer ring 71 and the rolling element 74) are completely separated by a fluid film).

[0072] In lithium-based (lithium grease) systems, when the rotation speed is continuously increased at 150 rpm for 2200 h, the noise OA value increases by 6 dB compared to the initial continuous rotation. Therefore, it is assumed that boundary lubrication occurs at the point when the noise OA value begins to increase, i.e., when the continuous rotation time exceeds 1000 h. At this point, the parameter Λ is estimated to be Λ < 1.

[0073] On the other hand, in the urea system (second urea grease G2), the noise OA value when continuously rotating at 150 rpm for 10,000 h is equal to the noise OA value after initially rotating at 150 rpm (0 h). Furthermore, the noise OA value when continuously rotating at 50 rpm for 10,000 h is equal to the noise OA value after initially rotating at 50 rpm (0 h). Furthermore, the noise OA value when continuously rotating at 50 rpm is equal to the noise OA value when continuously rotating at 150 rpm. That is, in the urea system, when continuously rotating within the speed range of 50 rpm to 150 rpm, even if the continuous rotation time increases, it does not cause an increase in noise. Furthermore, the parameter Λ at this time is 1 < Λ < 3, therefore the state of temporary metal contact should continue for a long time, but... Figure 5 As shown, it does not cause an increase in noise associated with increasing continuous rotation time. Therefore, it is believed that when using urea-based grease (second urea grease G2) as the lubricant, even when the parameter Λ is in the range of 1 < Λ < 3, metal-to-metal contact can be suppressed.

[0074] When lithium-based grease (lithium grease) is used as the grease, the changes in the composition of the thickener contained in the lithium grease due to the frictional heat associated with the rotation of the rolling element 74 are mainly oxidation. However, when urea-based grease (first urea grease G1, second urea grease G2) is used as the grease, the changes in the composition of the thickener in the urea grease due to the frictional heat associated with the rotation of the rolling element 74, in addition to oxidation, also result in hardening.

[0075] Here, as Figure 6 As shown, the curing of grease G refers to the phenomenon where the urea component (urea compound) U, which is adhered to the metal surface, oxidizes and forms a film on the metal surface. More specifically, the urea groups (-NHCONH-) contained in the urea grease adhering to the metal surface oxidize and change into carboxylic acids (-NHCOOH), thereby protecting the metal surface with a carboxylic acid film. In this embodiment, the oxidized urea component U of grease G is adhered to the rolling element 74, outer ring 71, and inner ring 72 (the oxidized urea component U is also adhered to the outer ring 81 and inner ring 82 in the same way as the outer ring 71 and inner ring 72). That is, the metal surface (rolling element 74, outer ring 71, inner ring 72) is protected by the oxidized urea component U (carboxylic acid), so even if the rolling element 74 rotates at a low speed, direct contact (metal contact) with the outer ring 71 (inner ring 72, outer ring 81, inner ring 82) can be suppressed.

[0076] Therefore, it is presumed that even in the case of either a boundary lubrication zone (Λ<1) or a mixed lubrication zone (1<Λ<3), by using a urea-based grease (urea grease) as the lubricant as in this embodiment, direct metal-to-metal contact can be suppressed by the film of the urea component U adhering to the metal surface. Thus, by using urea-based greases (first urea grease G1, second urea grease G2) as the lubricant, abnormal noise caused by metal-to-metal contact can be suppressed even when the motor 1 operates continuously at low speed for a long time. Furthermore, by suppressing metal-to-metal contact within the bearing, damage to the bearing can be suppressed.

[0077] Figure 7 This is a conceptual diagram representing the Stribek curve. (Example) Figure 7 As shown, the vertical axis is the coefficient of friction within the bearing (e.g., the coefficient of friction between the outer ring 71 and the rolling element 74), and the horizontal axis is the bearing constant that varies depending on the viscosity of the grease, the rotational speed, and the load.

[0078] like Figure 7 As shown, 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, it is known that 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. That is, even at the same rotational speed and under the same 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. Therefore, the coefficient of friction is lower when using urea grease compared to using lithium grease. In other words, by using urea grease, continuous operation for a longer period is possible even at lower rotational speeds compared to using lithium grease.

[0079] In this embodiment, the air supply device F, through the above-described structure, enables the motor 1 to operate continuously (maintain) in a low-speed rotation mode for a period of more than 5 hours. Furthermore, in this embodiment, the air supply device F enables the motor 1 to operate continuously (maintain) in a low-speed rotation mode for a period of more than 24 hours, thus enabling the motor 1 to operate throughout the day.

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

[0081] [Refrigeration cycle unit] Figure 8 This is a refrigerant circuit diagram illustrating a refrigeration cycle device equipped with the air supply device F of the present invention. The refrigeration cycle device is applied to an air conditioning unit 200 for cooling and heating indoors. The air conditioning unit 2000 includes an outdoor unit 210 and an indoor unit 270. The outdoor unit 210 includes 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 has a discharge port 231 as a discharge section and a suction port 232 as a suction section. The compressor 230 is controlled by the outdoor unit control unit 100A, thereby compressing the refrigerant supplied from the suction port 232 via the suction pipe 233 and the four-way valve 240, and supplying the compressed refrigerant from the discharge port 231 to the four-way valve 240 via the discharge pipe 234.

[0083] The four-way valve 240 is connected to the discharge pipe 234 and the suction pipe 233, and is 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, thereby switching the air conditioning unit 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 via the discharge pipe 234 to the outdoor heat exchanger 250, and supplies refrigerant flowing 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 via the discharge pipe 234 to the indoor unit 270, and supplies refrigerant flowing 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 piping 430. An outdoor air supply device F1 is located near the outdoor heat exchanger 250. The outdoor air supply device F1 is rotated by a first motor 1A, thereby drawing in external gas into the outdoor unit 210 and releasing the external gas, which has undergone heat exchange with the refrigerant through 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 external gas drawn into the outdoor unit 210, and supplies the refrigerant after heat exchange 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 external gas drawn into the outdoor unit 210, and supplies the refrigerant after heat exchange to the four-way valve 240.

[0085] Expansion valve 260 is connected to indoor unit 270 via refrigerant piping 430. In cooling mode, expansion valve 260 depressurizes the refrigerant supplied from outdoor heat exchanger 250 by adiabatic expansion, supplying a low-temperature, low-pressure two-phase refrigerant to indoor unit 270. In heating mode, expansion valve 260 depressurizes the refrigerant supplied from indoor unit 270 by adiabatic expansion, supplying a low-temperature, low-pressure two-phase refrigerant to outdoor heat exchanger 250. Furthermore, the opening of expansion valve 260 is adjusted by outdoor unit control unit 100A, regulating the flow rate of refrigerant supplied from indoor unit 270 to outdoor heat exchanger 250 in heating mode, and regulating the flow rate of refrigerant supplied from outdoor heat exchanger 250 to indoor unit 270 in cooling mode.

[0086] The indoor unit 270 includes an indoor heat exchanger 280, an indoor fan 150A (air blower), and an indoor unit control unit 100B. The indoor fan 150A (air blower) is located near the indoor heat exchanger 280 and is rotated by a second motor 1B to draw indoor air into the interior of the indoor unit 270 and release the indoor air that has undergone heat exchange 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 refrigerant piping 420 and to the expansion valve 260 of the outdoor unit 210 via refrigerant piping 430. The indoor heat exchanger 270 functions as an evaporator when the air conditioning unit 200 is switched to cooling mode and as a condenser when the air conditioning unit 200 is switched to heating mode. Specifically, 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 drawn into the indoor unit 270, releasing the exchanged indoor air back into the room and supplying the 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 drawn into the indoor unit 270, releasing the exchanged indoor air back into the room and supplying the exchanged refrigerant to the expansion valve 260.

[0088] Figure 9 This is a cross-sectional view of the main part of the heat source side unit (outdoor unit 210) of the refrigeration cycle device (air conditioning unit 200) equipped with the air supply device F (outdoor air supply device F1) of the present invention, viewed from the side. The first motor 1A corresponds to the motor 1 in the air supply device F of the present invention. The support leg 11 of the first motor 1A, which protrudes to the outer peripheral surface of the resin outer contour 10, is fixed to the support platform 220 of the outdoor unit 210. An impeller 300 is installed at the output end 61 (impeller fixing part) of the shaft 6 of the first motor 1A. The impeller 300 provided in the air supply device F1 in this embodiment is a propeller fan (axial flow fan).

[0089] The impeller 300, i.e., the propeller fan, of the air supply device F (outdoor air supply device F1) in this embodiment weighs 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) supporting the propeller fan is approximately 36 N. Thus, when the radial load applied to the bearings supporting the impeller 300 is large (e.g., 10 N or more, particularly 20 N or more), the lubricant film thickness in the bearings (first bearing 7, second bearing 8) of the motor 1 is easily insufficient, leading to a problem of abnormal noise, especially when the motor 1 is driven at low speed. Therefore, in this embodiment, even when the motor 1 is driven at low speed under a large radial load on the output end 61, by using urea grease G as the lubricant in the bearings (7, 8) of the motor 1, the generation of metal-to-metal contact within the bearings can be prevented, thus suppressing the generation of abnormal noise in the bearings.

[0090] Furthermore, in this embodiment, the electric motor 1 is described as being used as an air supply device F1 (outdoor fan) mounted on the heat source side unit (outdoor unit 210) of the refrigeration cycle unit (air conditioning unit 200). However, it is not limited to this and can also be used as an indoor air supply device F2 (indoor fan 150B) mounted on the utilization side unit (indoor unit 270) of the refrigeration cycle unit (air conditioning unit 200). Similarly, the electric motor 1 can also be used as both the outdoor air supply device F1 (outdoor fan 150A) mounted on the heat source side unit (outdoor unit 210) of the refrigeration cycle unit (air conditioning unit 200) and the indoor air supply device F2 (indoor fan 150B) mounted on the utilization side unit (indoor unit 270). Furthermore, in this embodiment, the impeller 300 of the air supply device F (outdoor fan 150A) equipped with motor 1 is exemplified as an axial fan (propeller fan, etc.), but it is not limited to this; the impeller 300 of the air supply device F equipped with motor 1 can also be a centrifugal fan (Sirocco fan, turbine fan, etc.) or a cross-flow fan (cross-flow fan, etc.). Additionally, as the heat source side unit of the refrigeration cycle device equipped with outdoor air supply device F1, an outdoor unit of an air conditioning unit is exemplified, but it is not limited to this; the outdoor air supply device F1 can also be mounted in a cooling unit (not shown). Furthermore, as the utilization side unit of the refrigeration cycle device equipped with indoor air supply device F2, an indoor unit of an air conditioning unit is exemplified, but it is not limited to this; the air supply device F1 can also be mounted in a fan coil unit (not shown).

[0091] Air purifier Furthermore, in this embodiment, the air supply device F equipped with the electric motor 1 is described as an outdoor air supply device F1 installed in the outdoor unit 210 of the air conditioning unit 200, but it is of course not limited to this and can also be used in an air purifier. Figure 10 This is a cross-sectional view taken longitudinally from the center of the air purifier 500 equipped with the air supply device F.

[0092] like Figure 10 As shown, the air purifier 500 has an internal airflow path 510 that guides air introduced from the air intake 511 to the air outlet 512. An air supply device F3 is provided midway through this airflow path 510 to allow air within the airflow path 510 to flow from the air intake 511 towards the air outlet 512. The air supply device F3's blower 150C is configured as a Sirocco fan 1C equipped with a motor 1C. The impeller 300 of this blower 150C preferably uses a Sirocco fan 1C as a centrifugal fan, but it is not limited to this; any fan that functions to circulate air is acceptable. For example, an axial fan, a cross-flow fan, or other types of fan can also be used as the impeller 300.

[0093] Furthermore, the air supply path 510 between the air intake 511 and the blower 150C is equipped with a pre-filter 520, a dust collection filter 521, a deodorization unit 530, a unit guide 531, and a humidification unit 540. Additionally, the air supply path 510 between the blower 150C and the air outlet 512 is equipped with an ozone generator 550 for sterilizing and deodorizing the air.

[0094] That is, 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) and discharged to the surroundings. At this time, the air supply device F3, by setting the motor 1C that drives the blower (fan) 150C to the above-described structure, enables the air purifier 500 to operate continuously for a long time while the blower (fan) 150C is rotating at a low speed.

[0095] Furthermore, in this embodiment, the air supply device F equipped with the electric motor 1 is described as the air supply device F1 installed in the heat source side unit (outdoor unit 210 of the air conditioning unit) of the refrigeration cycle device (air conditioning unit 200), but it is of course not limited to this and can also be used in the ventilation unit 600. Figure 11 This is a concept diagram of an air exchange unit 600 equipped with an air supply device F.

[0096] like Figure 11 As shown, the ventilation unit 600 includes a housing 610 that houses the total heat exchanger 620. The housing 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. Furthermore, an air supply passage 621 and an exhaust passage 622 are formed within the interior space of the housing 610. The air supply passage 621 is connected to the outdoor air supply port 611 at one end and to the indoor air supply port 612 at the other end. The exhaust passage 622 is connected to the indoor exhaust port 613 at one end and to the outdoor exhaust port 614 at the other end.

[0097] The total heat exchanger 620 can be a rotary total heat exchanger or a stationary total heat exchanger. The supply-side passage 621 and the exhaust-side passage 622 both pass through the total heat exchanger 620. That is, the supply-side passage 621 passes through one flow path of the total heat exchanger 620, and the exhaust-side passage 620 passes through the other flow path of the total heat exchanger 622. In other words, the total heat exchanger 620 is located midway through the supply-side passage 621 and midway through the exhaust-side passage 622.

[0098] In the ventilation unit 600, outdoor air flows towards the interior through the supply-side passage 621, and indoor air flows towards the outside through the exhaust-side passage 622. The indoor air flowing in the supply-side passage 621 and the indoor air flowing in the exhaust-side passage 622 exchange sensible and latent heat in the total heat exchanger 620. Thus, total heat exchange occurs between the air flowing in the supply-side passage 621 and the air flowing in the exhaust-side passage 622.

[0099] The ventilation unit 600 also includes a supply fan 150d (air blower) and an exhaust fan 150e (air blower). The supply fan 150d is located downstream of the total heat exchanger 620 in the supply side passage 621 (i.e., the indoor air supply port 612 side). The exhaust fan 150e is located downstream of the total heat exchanger 620 in the exhaust side passage 622 (i.e., the outdoor exhaust port 614 side).

[0100] 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, respectively, and controls the speed of each motor (1d, 1e). Furthermore, the control unit 630 can be any structure capable of controlling the speeds of motors 1d and 1e, and can be located either inside or outside the ventilation unit 630. Alternatively, the control unit 630 can be separated into two control units that control motors 1d and 1e respectively.

[0101] Figure 11 The ventilation unit 600 shown exhausts indoor air to the outside by rotating the impeller 300 of the exhaust fan 150e (ventilator) of the air supply device F4. By equipping the motor 1e driving the exhaust fan 150e (ventilator) with the aforementioned structure, the ventilation unit 600 equipped with the air supply device F4 can operate continuously for extended periods while the exhaust fan 150e is rotating at low speed. Furthermore, this example illustrates the use of urea grease in the motor 1e of the exhaust fan 150e, with the motor 1e rotating continuously at low speed for an extended period via the control unit 630. However, urea grease can also be used in the motor 1d of the air supply fan 150d, with the motor 1d rotating continuously at low speed for an extended period via the control unit 630.

[0102] Furthermore, this description uses an air exchange unit 600 equipped with a heat exchanger (total heat exchanger 620) as an example, but it may also be an air exchange unit without a heat exchanger. Additionally, this description uses an air exchange unit having passages on both the supply side passage 621 and the exhaust side passage 622 as an example, but it may also be an air exchange unit having only one of the supply side passage 621 or the exhaust side passage 622.

[0103] Furthermore, in this embodiment, the electric motor 1 is not limited to the examples described above, and can be used for various other purposes. For example, it can also be used in a bathroom heater.

[0104] That is, in bathroom heating, by rotating the impeller 300 of the air supply device F relative to the piping that circulates the heated hot water toward the bathroom, warm air can be supplied to the bathroom. At this time, by setting the motor 1 that drives the fan to the above structure, even if the blower (fan) 150 of the air supply device F rotates at low speed, it can operate continuously for a long time.

[0105] Explanation of reference numerals in the attached figures 1: Electric motor 2: Stator 3: Rotor 4: Bracket 5: Circuit board 6: Axis 61: Output end (impeller fixing part) 7: First bearing 8: Second bearing 10: Resin Outer Contour 71: Outer ring 72: Inner Circle 73: Retainer 74: Rolling element 100: Control Department 150: Blower (fan) 200: Air conditioning unit (refrigeration cycle unit) 210: Outdoor unit (heat source side unit) 270: Indoor unit (using side unit) 300: Impeller F: Air supply device G: Lubricating grease W: Bearing space.

Claims

1. An air supply device, comprising: An electric motor has a stator, a rotor disposed inside the stator, a shaft fixed to the rotor, and bearings that rotatably support the shaft, and the motor's rotational speed is changeable; and The control unit controls the speed of the motor. The control unit has at least one rotation mode that sets the speed n of the electric motor to a speed that satisfies 50 rpm ≤ n < 100 rpm. The bearing has an inner ring, an outer ring, a plurality of rolling elements disposed within an annular bearing space, and a urea-based grease filled within the bearing space, the bearing space being formed between the inner ring and the outer ring. The air supply device enables the motor to maintain the rotation mode for a period of time longer than 5 hours.

2. The air supply device according to claim 1, wherein, The air supply device enables the rotation mode to be maintained for a longer period of time than 24 hours.

3. The air supply device according to claim 1, wherein, In the rotating mode, the rotational speed n of the motor satisfies 50rpm≤n<80rpm.

4. The air supply device according to claim 3, wherein, The urea-based grease comprises a base oil, additives, and a thickener, wherein the thickener comprises a urea group. The base oil has a kinematic viscosity ν of 40 mm at 40°C. 2 / s or more.

5. The air supply device according to claim 4, wherein, The base oil has a kinematic viscosity ν of 80 mm at 40°C. 2 / s or more.

6. The air supply device according to claim 1, wherein, The motor also has an impeller fixing part for mounting the impeller on one end of the shaft.

7. The air supply device according to claim 6, wherein, The radial load applied to the bearing is 10N or more.

8. A heat source side unit of a refrigeration cycle device, comprising the air supply device as described in claim 1.

9. A utilization side unit of a refrigeration cycle apparatus, comprising the air supply device as described in claim 1.

10. A refrigeration cycle apparatus comprising at least one of the heat source side unit of claim 8 and the utilization side unit of claim 9.

11. A ventilation unit comprising the air supply device as described in claim 1.

12. An air purifier comprising the air supply device as described in claim 1.

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