JP2020150757A - Motor and state detection device of motor - Google Patents

Abstract

To improve reliability of a bearing in a motor.SOLUTION: A motor comprises: a rotor having a rotational axis 23; a stator 24 arranged to face a peripheral direction of the rotor; and a pair of bearing parts 22A and 22B rotatably supporting the rotational axis 23. The pair of bearing parts 22A and 22B comprises: a first bearing 221 which can be rotated with the rotational axis 23; and a second bearing 222 which can be rotated with the first bearing 221, respectively. When the first bearing 221 is normal, the first bearing 221 rotates with the rotational axis 23. When the first bearing 221 is abnormal, the second bearing 222 rotates with the first bearing 221 as well as the rotational axis 23.SELECTED DRAWING: Figure 2

Description

The present invention relates to a motor and a state detection device for the motor.

One of the causes of the failure of the motor is an abnormality such as a failure of the bearing that supports the rotating shaft attached to the rotor.

In addition, in order to appropriately diagnose the presence or absence of signs of bearing failure in the motor, the first temperature sensor that detects the temperature of the first bearing installed on one end side of the shaft member of the electric motor (motor), the shaft member, and others. A second temperature sensor that detects the temperature of the second bearing installed on the end side, and the presence or absence of a failure sign of the first bearing and the second bearing based on the difference between the temperature of the first bearing and the temperature of the second bearing. A bearing failure sign diagnostic means for diagnosing is known (see Patent Document 1).

Japanese Unexamined Patent Publication No. 2015-231295

If an abnormality occurs in the bearing of the motor, the rotation of the rotor will be hindered, so it is necessary to replace the bearing. In particular, a motor for a cooling fan for cooling the inside of a server (hereinafter referred to as a "fan motor") is required to have high reliability because a failure of the fan motor interferes with the use of the server. .. The high reliability of a bearing in a fan motor specifically means that the period until an abnormality occurs in the bearing, that is, the life of the bearing is long, or the life of the bearing can be predicted.

However, in the technique of Patent Document 1, although the life of the bearing can be predicted, it has not been considered to extend the life of the bearing. Further, in the technique of Patent Document 1, since it is necessary to provide a temperature sensor for each of the two bearings, it is necessary to secure a mounting place for the temperature sensor, and the configuration of the motor is complicated.

The present invention is an example of the above-mentioned problems, and an object of the present invention is to provide a technique capable of improving the reliability of bearings in a motor.

In order to achieve the above object, the motor according to the present invention includes a rotor having a rotating shaft, a stator arranged so as to face each other in the circumferential direction of the rotor, and a pair of bearings that rotatably support the rotating shaft. The pair of bearing portions each include a first bearing that can rotate with the rotating shaft and a second bearing that can rotate with the first bearing, and the first bearing is normal. When the first bearing rotates with the rotating shaft, and when the first bearing becomes abnormal, the second bearing also rotates with the rotating shaft with the first bearing.

In the motor according to one aspect of the present invention, the first bearing includes a first inner ring that can rotate together with the rotating shaft, a first outer ring provided on the outer peripheral side of the first inner ring, and the first inner ring. It has a first rolling element arranged between the first outer ring, and the second bearing is provided on the outer peripheral side of the second inner ring and the second inner ring that can rotate with the first outer ring. It has a second outer ring and a second rolling element arranged between the second inner ring and the second outer ring.

In the motor according to one aspect of the present invention, the second bearing is provided at a position separated from the first bearing in the axial direction of the rotating shaft.

In the motor according to one aspect of the present invention, the second bearing is provided on the outer peripheral side of the first bearing.

In the motor according to one aspect of the present invention, the pair of bearing portions each include a coupling portion that rotatably connects the first outer ring and the second inner ring.

In the motor according to one aspect of the present invention, the first bearing has a kinematic viscosity lower than the kinematic viscosity of the second bearing.

In order to achieve the above object, the motor state detection device according to the present invention is a device that detects the state of the bearing portion of the motor, and acquires information that is information based on the rotational motion of the motor. A unit and a state detection unit that detects the state of rotational motion of the bearing unit based on the rotation information acquired by the information acquisition unit are provided.

In the motor state detection device according to one aspect of the present invention, the rotation information is information regarding the rotation speed of the rotor.

In the motor state detection device according to one aspect of the present invention, the rotation information is information regarding the motor current of the motor.

In the motor state detection device according to one aspect of the present invention, it is determined which of the first bearing and the second bearing is rotating with the rotation shaft in the bearing portion based on the rotation information.

According to the present invention, the reliability of bearings in a motor can be improved.

It is a front view which shows typically the structure of the fan apparatus which comprises the motor of 1st Embodiment which concerns on this invention. FIG. 5 is a cross-sectional view schematically showing the configuration of the fan device shown in FIG. FIG. 5 is a cross-sectional view schematically showing a configuration of a rotating shaft and a bearing portion included in the fan device shown in FIG. 1. It is a flowchart for showing the transition of the operation of the bearing part of the motor provided in the fan device shown in FIG. It is a schematic diagram which shows the transition between the rotation speed of the motor provided in the fan device shown in FIG. 1 and the motor current. It is a functional block diagram of the drive control device of the motor which concerns on embodiment of this invention. It is a flowchart for showing an example of the state detection processing of the bearing part by the drive control device of the motor shown in FIG. It is a flowchart for showing the modification of the state detection process of the bearing part by the drive control device of the motor shown in FIG. It is sectional drawing which shows typically the structure of the rotating shaft and the bearing part provided with the motor which concerns on 2nd Embodiment of this invention.

Hereinafter, the motor and the motor state detection device according to the embodiment of the present invention will be described with reference to the drawings.

<First Embodiment of Motor>
FIG. 1 is a front view schematically showing a configuration of a fan device 1 including a motor 10 according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing the configuration of the fan device 1. FIG. 3 is a cross-sectional view schematically showing the configuration of the rotating shaft 23 and the bearing portion 22 included in the fan device 1.

In the following description, for convenience, the arrow a direction is the upper side a and the arrow b direction is the lower side b in the axis x direction. Further, in the radial direction perpendicular to the axis x, the direction away from the axis x (direction of arrow c in FIG. 1) is defined as the outer peripheral side c, and the direction toward the axis x (direction of arrow d in FIG. 1) is defined as the inner peripheral side d. .. In the following description, for convenience, the direction shown in FIG. 1 is referred to as the side surface of the motor. Further, in the following description, for convenience, the direction in which the motor is viewed from the upper side a toward the lower side b is the front surface, and the direction in which the motor is viewed from the lower side b toward the upper side a is the bottom surface.

As shown in FIGS. 1 to 3, the motor 10 according to the present embodiment is provided in the fan device 1 and has a rotor having a rotating shaft 23 and a stator arranged so as to face each other in the circumferential direction of the rotor. 24 and a pair of bearing portions 22A and 22B that rotatably support the rotating shaft 23, and the pair of bearing portions 22A and 22B include a first bearing 221 and a first bearing 221 that can rotate together with the rotating shaft 23. When the first bearing 221 is normal, the first bearing 221 rotates together with the rotating shaft 23, and when the first bearing 221 becomes abnormal, the first bearing is provided. Along with 221 the second bearing 222 also rotates with the rotating shaft 23. Hereinafter, the configuration and operation of the fan device 1 including the motor 10 will be specifically described.

[Fan device configuration]
As shown in FIG. 1, the fan device 1 includes an impeller 30 having a plurality of blades 28 on the hub 25, and a casing 40 that covers the outer periphery of the impeller 30 and determines the outer shape of the fan device 1. The impeller 30 has a hub 25 arranged in a central portion centered on the axis x inside the casing 40. As shown in FIG. 2, in the fan device 1, the motor 10 is arranged inside the hub 25 of the impeller 30.

The motor 10 is, for example, an outer rotor type brushless DC (Direct Current) motor in which a rotating shaft 23, a rotor yoke 26 connected to the rotating shaft 23, and an impeller 30 form a rotor. The motor 10 includes a rotating shaft 23, a bearing housing 21, a pair of bearing portions 22A and 22B, a stator 24, a rotor yoke 26, and a magnet 27.

As shown in FIGS. 2 and 3, the rotating shaft 23 is a rod-shaped member arranged with the axis x direction as the longitudinal direction. The bearing housing 21 is a hollow tubular body supported by the central portion of the casing 40. The bearing housing 21 rotatably supports the rotating shaft 23 via a pair of bearing portions 22A and 22B. The bearing housing 21 has a bearing support portion 212 that supports the bearing portion 22A at one end of the cylindrical housing body 211 in the axis x direction and a bearing support portion that supports the bearing portion 22B at the other end of the housing body 211 in the axis x direction. 213 and. The bearing support portions 212 and 213 are formed on the inner peripheral surfaces of the housing body 211, respectively.

Specifically, the pair of bearing portions 22A and 22B are the bearing portion 22A supported by the bearing support portion 212 provided at one end in the axis x direction of the bearing housing 21 and the axis of the bearing housing 21 as described above. It is a bearing portion 22B supported by a bearing support portion 213 provided at the other end in the x direction. The pair of bearing portions 22A and 22B include a first bearing 221 and a second bearing 222, and a coupling portion 223, respectively. As shown in FIG. 3, in each of the pair of bearing portions 22A and 22B, the second bearing 222 is provided at a position separated from the first bearing 221 in the axis x direction of the rotating shaft 23.

The first bearing 221 includes a first inner ring 2211, a first outer ring 2212, and a first rolling element 2213. The first inner ring 2211 is an annular member having an inner peripheral surface that can be mounted on the outer peripheral surface 23a of the rotating shaft 23. The first inner ring 2211 can rotate together with the rotating shaft 23 by being mounted on the outer peripheral surface 23a of the rotating shaft 23. The first outer ring 2212 is provided on the outer peripheral side c of the first inner ring 2211. The first outer ring 2212 is an annular member coaxial with the first inner ring 2211 and having a diameter larger than that of the first inner ring 2211. The first rolling element 2213 is a spherical member arranged between the first inner ring 2211 and the first outer ring 2212. In the first bearing 221, a lubricant is sealed between the first inner ring 2211, the first outer ring 2212, and the first rolling element 2213.

The second bearing 222 includes a second inner ring 2221, a second outer ring 2222, and a second rolling element 2223. The second inner ring 2221 is an annular member having an inner peripheral surface that can be attached to the coupling portion 223. By being attached to the coupling portion 223, the second inner ring 2221 can rotate together with the first outer ring 2212 via the coupling portion 223. The second outer ring 2222 is provided on the outer peripheral side c of the second inner ring 2221. The second outer ring 2222 is an annular member coaxial with the second inner ring 2221 and having a diameter larger than that of the second inner ring 2221. The second rolling element 2223 is a spherical member arranged between the second inner ring 2221 and the second outer ring 2222. In the second bearing 222, a lubricant is sealed between the second inner ring 2221, the second outer ring 2222, and the second rolling element 2223.

The first bearing 221 and the second bearing 222 have different kinematic viscosities from each other due to differences in the mechanical friction coefficient of the components used for each and the viscosity of the lubricant. In the present embodiment, the first bearing 221 has, for example, a kinematic viscosity lower than the kinematic viscosity of the second bearing 222.

The coupling portion 223 includes a first bearing accommodating portion 2231, a second bearing accommodating portion 2232, and a step portion 2233. The coupling portion 223 is a step connecting the first bearing accommodating portion 2231 and the second bearing accommodating portion 2232, which are tubular portions having different radial dimensions, and the first bearing accommodating portion 2231 and the second bearing accommodating portion 2232. The first outer ring 2212 and the second inner ring 2221 are rotatably connected by the portion 2233.

The first bearing accommodating portion 2231 has an inner peripheral surface capable of accommodating the first outer ring 2212 of the first bearing 221. Specifically, the first bearing accommodating portion 2231 is formed in a shape and size that can rotate in cooperation with the first outer ring 2212.

The second bearing accommodating portion 2232 has an inner peripheral surface having a shape and size having a predetermined gap with respect to the outer peripheral surface 23a of the rotating shaft 23. Further, the second bearing accommodating portion 2232 has an outer peripheral surface capable of accommodating the second inner ring 2221 of the second bearing 222. The second bearing accommodating portion 2232 is formed in a shape and size that can rotate in cooperation with the second inner ring 2221.

The stator 24 is fixed to, for example, the lower side b of the casing 40. The stator 24 includes, for example, a stator core 241 formed by laminating a plurality of electromagnetic steel plates, an insulator provided on the stator core, and a coil 242 wound on the stator core 241 via an insulator.

The rotor yoke 26 is provided, for example, on the inner peripheral portion of the hub 25 of the impeller 30. The rotor yoke 26 is formed in a substantially tubular shape, for example, for accommodating the magnet 27. The rotor yoke 26 may be formed separately from the hub 25 or may be formed integrally with the hub 25. The magnet 27 is attached to the inner peripheral surface of the rotor yoke 26. The magnet 27 is provided so as to have a predetermined gap with the stator 24 provided on the inner peripheral side d.

[Operation of fan device]
Next, the operation of the fan device 1 having the configuration described above will be described.

FIG. 4 is a flowchart for showing the transition of the operation of the bearing portions 22A and 22B of the motor 10 included in the fan device 1. As shown in FIG. 4, the motor 10 starts the rotation of the rotating shaft 23 when the driving current flows (step S11). As shown in FIGS. 2 and 3, the rotating shaft 23 of the motor 10 is rotatably supported by a pair of bearing portions 22A and 22B mounted on the bearing housing 21. Further, one end of the upper side a of the rotating shaft 23 is connected to the hub 25 of the impeller 30. Therefore, when the motor 10 is driven, the rotating shaft 23 rotates about the axis x, and the impeller 30 also rotates about the axis x accordingly.

Here, the motor 10 includes a first bearing 221 in which a pair of bearing portions 22A and 22B can rotate together with the rotating shaft 23, and a second bearing 222 that can rotate together with the first bearing 221. Here, the pair of bearing portions 22A and 22B have different kinematic viscosities of the first bearing 221 and the second bearing 222. That is, the motor 10 moves among the first bearing 221 and the second bearing 222 due to the difference in kinematic viscosity of the two bearings (first bearing 221 and second bearing 222) provided in the pair of bearing portions 22A and 22B, respectively. A bearing having a low viscosity (for example, the first bearing 221) is easier to rotate. In the bearing portions 22A and 22B of the motor 10 configured in this way, under normal conditions (predetermined time after operation), the first bearing 221 having low kinematic viscosity has a normal operation function. 1 The inner ring 2211 is supported by the first rolling element 2213 and the first outer ring 2212 and rotates together with the rotating shaft 23. In this way, in the first bearing 221 the state in which the first inner ring 2211 is supported by the first rolling element 2213 and the first outer ring 2212 and rotates together with the rotating shaft 23 is regarded as a normal state.

After that, in the motor 10, when the operating function of the first bearing 221 deteriorates or starts to fail in the bearing portions 22A and 22B, the friction coefficient of the first bearing 221 increases (step S12). In this way, the state in which the operating function of the first bearing 221 is deteriorated or malfunctions, an abnormality occurs, and the friction coefficient increases is defined as an abnormal state. In the bearing portions 22A and 22B, when the rotational torque of the first bearing 221 exceeds the starting torque of the second bearing 222, the rotation of the coupling portion 223 and the second bearing 222 starts (step S13). Specifically, in the bearing portions 22A and 22B, the first inner ring 2211 of the first bearing 221 and the first outer ring 2212 and the first rolling element 2213 are integrally rotated together with the rotating shaft 23. The inner peripheral surface of the first bearing accommodating portion 2231 is rotatably connected to the coupling portion 223 together with the first outer ring 2212 of the first bearing 221. In this way, when the first outer ring 2212 rotates together with the first inner ring 2211 in the first bearing 221, the second bearing 222 starts rotating (co-rotating) with the rotating shaft 23 via the coupling portion 223. (Step S14). That is, since the second inner ring 2221 of the second bearing 222 is attached to the outer peripheral surface of the second bearing accommodating portion 2232 of the coupling portion 223, it can rotate according to the rotation of the coupling portion 223. Therefore, in the motor 10, the coupling portion 223 and the second bearing 222 rotate together with the rotating shaft 23 (step S15).

According to the motor 10 configured as described above and the fan device 1 including the motor 10, the rotating shaft 23 is formed by the pair of bearing portions 22A and 22B having the first bearing 221 and the second bearing 222 having different kinematic viscositys. Since it is supported, even if the first bearing 221 is in an abnormal state such as deterioration or failure, the operation can be continued without replacing the bearing parts. That is, according to the motor 10 configured as described above and the fan device 1 including the motor 10, the motor 10 is always operated and maintenance work such as parts replacement work is performed, for example, like a fan for cooling a server. The life of the bearing can be extended even in applications where the time is limited.

FIG. 5 is a schematic view showing a transition between the rotation speed of the motor 10 included in the fan device 1 and the motor current. FIG. 5 shows changes in the rotational speed of the motor 10 and the values of the motor current according to the deterioration status of the bearing portions 22A and 22B from the start of operation of the motor 10. In FIG. 5, t0: at the start of operation of the motor 10, t1: when the first bearing 221 is not in a normal operating state (start of failure of the first bearing 221), t2: the first bearing 221 is rotated together with the coupling portion 223. When it starts to rotate integrally with 23 (the first bearing 221 rotates together with the inner and outer rings), each of them is shown. As shown in FIG. 5, the motor 10 is operated at a rotation speed: R2 and a motor current value: A1 because the first bearing 221 is operating normally in the period from t0 to t1. However, in the period from t1 to t2, the rotation speed of the motor 10 decreases from R2 and the motor current value changes from A1 due to the deterioration of the first bearing 221 and the gradual increase in the rotational torque of the first bearing 221. It is rising. After t2 has elapsed, the rotational torque of the first bearing 221 exceeds the starting torque of the second bearing 222, so that the second bearing 222 operates in the bearing portions 22A and 22B. Therefore, the rotational speed: R1, the motor current. Value: A2.

According to the motor 10 configured as described above and the fan device 1 including the motor 10, the rotating shaft 23 is formed by the pair of bearing portions 22A and 22B having the first bearing 221 and the second bearing 222 having different kinematic viscositys. Since it is supported, for example, by measuring the rotation speed of the motor 10 and the motor current, it is possible to easily recognize which of the first bearing 221 and the second bearing 222 is operating in the bearing portions 22A and 22B. Can be done. That is, according to the motor 10 configured as described above and the fan device 1 including the motor 10, the operating states of the bearing portions 22A and 22B can be easily recognized, so that the bearing portions 22A and 22B can be replaced. The time and life can be predicted.

Therefore, according to the motor 10 configured as described above and the fan device 1 including the motor 10, the reliability of the bearing can be improved.

Further, according to the motor 10 and the fan device 1 including the motor 10, the rotation of the rotating shaft 23 can be transmitted to the second bearing 222 when the first bearing 221 is deteriorated by the coupling portion 223, so that the reliability of the bearing is increased. Can be improved. Further, since the coupling portion 223 does not transmit rotation to the second bearing 222 when the first bearing 221 is operating normally, the reliability of the bearing is improved without causing loss in the bearing portions 22A and 22B. can do.

<Embodiment of Motor State Detection Device>
Next, an embodiment of the motor state detection device will be described.

In the present embodiment, the drive control device 3 of the motor 10 functions as a state detection device for detecting the states of the bearing portions 22A and 22B of the motor 10. The drive control device 3 has a rotation speed calculation unit 32 as an information acquisition unit that acquires rotation information that is information based on the rotational movement of the motor 10, and a bearing unit 22A, based on the rotation information acquired by the rotation speed calculation unit 32. A bearing abnormality determination unit 35 is provided as a state detection unit for detecting the state of the rotational movement of 22B. Hereinafter, the drive control device 3 of the motor 10 that functions as a motor state detection device will be described.

FIG. 6 is a functional block diagram of the drive control device 3 of the motor 10 according to the embodiment of the present invention. As shown in FIG. 6, the drive control device 3 of the motor 10 includes a speed command analysis unit 31, a rotation speed calculation unit 32, a PWM (Pulse Width Modulation) command unit 33, a PWM signal generation unit 34, and a bearing abnormality determination unit 35. Be prepared. The drive control device 3 is, for example, an information processing device such as an MCU (Micro Controller Unit) capable of executing various computer programs including a program for realizing the following functional blocks by the drive control device 3 according to the present invention. It is realized by a storage device such as a ROM (Read Only Memory) that stores a computer program or data at the time of program execution. In addition, the ROM also stores information on predetermined values of rotation information used in processing by the bearing abnormality determination unit 35, which will be described later.

The speed command analysis unit 31 receives the speed command signal Sc of the motor 10 from an external device (not shown) such as a server control unit, and generates a target rotation speed signal S1 for giving an instruction to the PWM command unit 33.

The rotation speed calculation unit 32 is the first hall signal Sh1 (information on the rotation speed) acquired by the hall sensor H1 attached to the motor 10 and provided to detect the rotation speed of the rotor (rotational shaft 23 or impeller 30). ) Is acquired as the actual rotation speed information of the rotor, and the rotation speed of the rotor is calculated. The rotation speed calculation unit 32 outputs the rotation speed signal S2 to the PWM command unit 33 and the bearing abnormality determination unit 35. Further, the rotation speed calculation unit 32 outputs the calculated rotation speed of the rotor to an external device as an FG (Frequency Generator) signal.

The PWM command unit 33 generates a PWM signal signal S3 that is generated based on the target rotation speed signal S1 output from the speed command analysis unit 31 and the rotation speed signal S2 output from the rotation speed calculation unit 32. Output to unit 34. The PWM setting instruction signal S3 is a signal for instructing the PWM signal setting generated by the PWM signal generation unit 34, that is, the duty ratio of the PWM signal required to drive the motor 10 at a desired rotation speed.

The PWM signal generation unit 34 generates and outputs a drive control signal Sd that controls the motor drive unit 2, that is, a PWM signal S4 having a desired duty ratio, based on the PWM setting instruction signal S3 output by the PWM command unit 33. ..

The motor drive unit 2 drives the motor 10 based on the drive control signal Sd. Further, the bearing abnormality determination unit 35 acquires the current signal S5, which is information on the motor current flowing through the motor drive unit 2, which is an example of the rotation information of the motor.

The bearing abnormality determination unit 35 is an information acquisition unit that acquires rotational information that is information based on the rotational motion of the motor 10, and a state of rotational motion of the bearing portions 22A and 22B based on the rotational information acquired by this information acquisition unit. Functions as a state detector to detect. Specifically, the bearing abnormality determination unit 35 has either the first bearing 221 or the second bearing 222 in the bearing units 22A and 22B based on at least one of the rotation speed signal S2 and the current signal S5, which are rotation information. It is determined whether or not the bearings are rotating together with the rotating shaft 23, and whether or not the first bearing 221 of the bearing portions 22A and 22B is in an abnormal state such as deterioration or failure is detected. When the bearing abnormality determination unit 35 detects an abnormality in the bearing units 22A and 22B, the bearing abnormality determination unit 35 outputs information indicating an abnormality state of the bearing units 22A and 22B to an external device as an abnormality notification signal Sa.

FIG. 7 is a flowchart for showing an example of the state detection processing of the bearing portions 22A and 22B by the drive control device 3 of the motor 10. In the example of the state detection processing of the bearing portions 22A and 22B by the drive control device 3 shown in FIG. 7, the bearing abnormality determination unit 35 has a rotation speed signal S2 which is information on the rotation speed of the motor as rotation information, and the motor drive unit 2 The state of the bearing portions 22A and 22B is detected based on the current signal S5, which is information on the motor current flowing through the bearing. As shown in FIG. 7, in the drive control device 3, the bearing abnormality determination unit 35 shows a predetermined value of the rotation speed of the motor, for example, FIG. 5, based on the rotation speed signal S2 output by the rotation speed calculation unit 32. It is determined whether or not it is R1 or more (S101).

When the rotation speed of the motor is equal to or less than a predetermined value (step S101: NO), the bearing abnormality determination unit 35 determines the motor current flowing through the motor 10 based on the current signal S5 which is information about the motor current flowing through the motor driving unit 2. Is less than a predetermined value, for example, A2 shown in FIG. 5 (step S102).

When the motor current flowing through the motor 10 exceeds a predetermined value (step S102: NO), the bearing abnormality determination unit 35 determines that the first bearing 221 of the bearing portions 22A and 22B is in an abnormal state of deterioration (step S103). ). As shown in FIG. 4, when the first bearing 221 deteriorates, the rotational torque of the first bearing 221 gradually increases, so that the rotational speed decreases from the normal state, and the motor current also changes from the normal state. To rise. Therefore, the bearing abnormality determination unit 35 detects that both the rotation speed of the motor 10 and the motor current have changed from normal values, and detects an abnormal state of the bearing units 22A and 22B, that is, the life. be able to.

On the other hand, when the rotation speed of the motor 10 is equal to or higher than a predetermined value (step S101: YES) or when the motor current of the motor 10 is less than a predetermined value (step S102: YES), the bearing abnormality determination unit 35 , It is determined that the first bearing 221 of the bearing portions 22A and 22B is operating normally (step S104).

FIG. 8 is a flowchart for showing a modified example of the state detection process of the bearing portions 22A and 22B by the drive control device 3 of the motor 10. In a modified example of the state detection processing of the bearing portions 22A and 22B by the drive control device 3 shown in FIG. 8, the bearing abnormality determination unit 35 uses the rotation speed signal S2, which is the rotation speed information of the motor, or the motor drive as rotation information. The state of the bearing portions 22A and 22B is detected based on any information of the current signal S5, which is information regarding the motor current flowing through the portion 2. As shown in FIG. 8, in the drive control device 3, the bearing abnormality determination unit 35 shows a predetermined value of the rotation speed of the motor, for example, FIG. 5, based on the rotation speed signal S2 output by the rotation speed calculation unit 32. It is determined whether or not it is R1 or more (step S201).

When the rotation speed of the motor 10 is equal to or higher than a predetermined value (step S201: YES), the bearing abnormality determination unit 35 moves the motor flowing through the motor 10 based on the current signal S5 which is information about the motor current flowing through the motor driving unit 2. It is determined whether or not the current is a predetermined value, for example, less than A2 shown in FIG. 5 (step S202).

When the rotation speed of the motor is equal to or less than a predetermined value (step S201: NO), or when the motor current flowing through the motor 10 exceeds a predetermined value (step S202: NO), the bearing abnormality determination unit 35 is subjected to the bearing unit 22A, It is determined that the first bearing 221 of 22B is in an abnormal state of deterioration (S203). In the modified example, similarly to the example described above, the bearing abnormality determination unit 35 detects that both the rotation speed of the motor 10 and the motor current have changed from the normal values, and the bearing units 22A and 22B. Abnormal state, that is, the life span can be detected.

On the other hand, when the motor current of the motor 10 is less than a predetermined value (step S202: YES), the bearing abnormality determination unit 35 determines that the first bearing 221 of the bearing units 22A and 22B is operating normally. (Step S204).

According to the drive control device 3 of the motor 10 configured as described above, the rotating shaft 23 is supported by a pair of bearing portions 22A and 22B having a first bearing 221 and a second bearing 222 having different kinematic viscositys. Since the operating state of the bearing portions 22A and 22B is determined based on the rotation information of the motor 10, for example, the rotation speed of the motor 10 and at least one of the motor currents, the bearing portion is determined. Which of the first bearing 221 and the second bearing 222 is operating in the 22A and 22B, that is, the operating state of the bearing portions 22A and 22B can be easily determined. That is, according to the drive control device 3 of the motor 10 configured as described above, the operating state of the bearing portions 22A and 22B of the motor 10 can be easily determined, so that it is time to replace the bearing portions 22A and 22B. , Life can be predicted.

Therefore, according to the drive control device 3 of the motor 10 configured as described above, the reliability of the bearing can be improved.

<Second Embodiment of Motor>
Next, a second embodiment of the motor according to the present invention will be described. In the motor according to the present embodiment, the same reference numerals are given to the same configurations as those of the motor 10 described above, and the description thereof will be omitted.

FIG. 9 is a cross-sectional view schematically showing the configuration of the rotating shaft 23 and the bearing portions 22Ab and 22Bb included in the motor according to the second embodiment of the present invention.

As shown in FIG. 9, the pair of bearing portions 22Ab and 22Bb included in the motor according to the second embodiment has the bearing portion 22Ab of the bearing housing 21b, similarly to the pair of bearing portions 22A and 22B described above. It is supported by a bearing support portion 212b provided at one end in the axis x direction, and a bearing portion 22Bb is supported by a bearing support portion 213b provided at the other end of the bearing housing 21b in the axis x direction.

In the pair of bearing portions 22Ab and 22Bb included in the motor according to the second embodiment, the first bearing 221b and the second bearing 222b of the bearing portions 22Ab and 22Bb are in a direction perpendicular to the axis x direction of the rotating shaft 23. It differs from the pair of bearing portions 22A and 22B described above in that they are arranged at positions. That is, in the pair of bearing portions 22Ab and 22Bb, the second bearing 222b is provided on the radial outside of the first bearing 221b, that is, on the outer peripheral side c of the first bearing 221b. Since the first bearing 221b and the second bearing 222b are arranged as described above, the pair of bearing portions 22Ab and 22Bb have the first outer ring 2212b of the first bearing 221b and the second inner ring 2221b of the second bearing 222b. It is different from the pair of bearing portions 22A and 22B described above in that they are in contact with each other. The pair of bearing portions 22Ab and 22Bb are configured so that the first outer ring 2212b of the first bearing 221b and the second inner ring 2221b of the second bearing 222b are in contact with each other and can rotate together with the first outer ring 2212. It differs from the pair of bearing portions 22A and 22B described above in that it does not have a coupling portion 223 connecting the second inner ring 2221.

According to the motor and fan device including the bearing portions 22Ab and 22Bb configured as described above, the rotating shaft 23 is formed by the pair of bearing portions 22Ab and 22Bb having the first bearing 221b and the second bearing 222b having different kinematic viscosity. Since it is supported, even if the first bearing 221b deteriorates or fails, the operation can be continued without replacing the bearing parts. That is, according to the motor and fan device including the bearing portions 22Ab and 22Bb configured as described above, for example, like a cooling fan of a server, the motor and fan device are always operated and maintenance work such as parts replacement work is performed. Bearing life can be extended even in limited time applications.

Therefore, according to the motor and fan device including the bearing portions 22A and 22B configured as described above, the reliability of the bearing can be improved.

In addition, those skilled in the art can appropriately modify the motor of the present invention and the state detection device for the motor according to conventionally known knowledge. As long as the modification still has the constitution of the present invention, it is, of course, included in the category of the present invention. For example, in the embodiment described above, the motor 10 is an outer rotor type brushless DC motor, but the type and structure of the motor are not limited to this in the present invention. Further, in the embodiment described above, when the first bearing 221 and the second bearing 222 of the bearing portions 22A and 22B are arranged at positions separated from each other in the axis x direction, the coupling portion 223 is used. Although the first outer ring 2212 and the second inner ring 2221 were connected, the present invention is not limited to this. For example, the first outer ring 2212 and the second inner ring 2221 may be connected by welding or the like to obtain the same action. Further, in the drive control device 3 of the motor 10, the abnormality notification signal Sa and the FG signal may be output on a common output line. Further, in the drive control device 3 of the motor 10, the predetermined values of the rotation speed signal S2 and the current signal S5 of the motor 10 used for the abnormality determination are not limited to the above examples, and arbitrary values can be adopted. Further, the motor current used for abnormality determination is not limited to the current flowing in the motor drive unit, and may be the current flowing in other circuit parts.

1 ... Fan device, 2 ... Motor drive unit, 3 ... Drive control device, 10 ... Motor, 20 ... Rotating shaft, 21,21b ... Bearing housing, 22A, 22B, 22Ab, 22Bb ... Bearing part, 23 ... Rotating shaft, 23a ... outer peripheral surface, 24 ... stator, 25 ... hub, 26 ... rotor yoke, 27 ... magnet, 28 ... blades, 30 ... impeller, 31 ... speed command analysis unit, 32 ... rotation speed calculation unit, 33 ... PWM command unit, 34 ... PWM signal generation unit, 35 ... bearing abnormality determination unit, 40 ... casing, 211,211b ... housing body, 212,212b ... bearing support part, 213,213b ... bearing support part, 221,221b ... first bearing, 222,222b ... 2nd bearing, 223 ... Coupling part, 241 ... Stator core, 242 ... Coil, 221,2211b ... 1st inner ring, 2212, 2212b ... 1st outer ring, 2213, 2213b ... 1st rolling element, 2221,221b ... Second Inner ring, 2222, 2222b ... 2nd outer ring, 2223, 2223b ... 2nd rolling element, 2231 ... 1st bearing accommodating portion, 2232 ... 2nd bearing accommodating portion, 2233 ... Step portion

Claims (10)

A rotor with a rotating shaft and
With the stator arranged so as to face the circumferential direction of the rotor,
A pair of bearing portions that rotatably support the rotating shaft are provided.
The pair of bearings
A first bearing that can rotate with the rotating shaft,
A second bearing that can rotate together with the first bearing is provided.
When the first bearing is normal, the first bearing rotates with the rotating shaft, and when the first bearing becomes abnormal, the second bearing rotates with the rotating shaft together with the first bearing.
motor. The first bearing is
A first inner ring that can rotate together with the rotation shaft, a first outer ring provided on the outer peripheral side of the first inner ring, and a first rolling element arranged between the first inner ring and the first outer ring. And have
The second bearing is
A second inner ring that can rotate together with the first outer ring, a second outer ring provided on the outer peripheral side of the second inner ring, and a second roll arranged between the second inner ring and the second outer ring. Have a moving body,
The motor according to claim 1. The second bearing is provided at a position separated from the first bearing in the axial direction of the rotating shaft.
The motor according to claim 2. The second bearing is provided on the outer peripheral side of the first bearing.
The motor according to claim 2. The pair of bearings
Each includes a coupling portion that rotatably connects the first outer ring and the second inner ring.
The motor according to claim 2 or 3. The first bearing has a kinematic viscosity lower than the kinematic viscosity of the second bearing.
The motor according to any one of claims 1 to 5. A device for detecting the state of the bearing portion of the motor according to any one of claims 1 to 6.
An information acquisition unit that acquires rotation information, which is information based on the rotational movement of the motor,
A state detection unit that detects the state of rotational motion of the bearing unit based on the rotation information acquired by the information acquisition unit, and a state detection unit.
A motor state detector. The rotation information is information regarding the rotation speed of the rotor.
The motor state detection device according to claim 7. The rotation information is information regarding the motor current of the motor.
The motor state detection device according to claim 7 or 8. The state detection unit determines which of the first bearing and the second bearing is rotating with the rotation shaft in the bearing unit based on the rotation information.
The motor state detection device according to any one of claims 7 to 9.

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