Cooling structure of bidirectional electric motor using variable guide vane installed in fan cover of centrifugal fan

Abstract

Provided is a cooling structure of a bidirectional electric motor using a variable guide vane installed in a fan cover of a centrifugal fan. An electric motor system according to an embodiment of the present invention comprises: an electric motor which is rotatable bidirectionally; a centrifugal fan which is rotated in conjunction with the electric motor in order to cool the electric motor; a fan cover surrounding the centrifugal fan; and variable guide vanes which are disposed inside the centrifugal fan cover at the outer periphery of the fan and have a variable torsion angle. Accordingly, a recirculation flow generated inside the fan cover by means of the centrifugal fan can be reduced, and thus, a cooling flow rate transferred to the electric motor can be increased, thereby improving cooling efficiency.

Description

Cooling structure of a bidirectional electric motor utilizing variable guide vanes installed on the fan cover of a centrifugal fan

[0001] The present invention relates to a bidirectional electric motor cooling technology, and more specifically, to a cooling structure that improves the cooling efficiency of an electric motor by reducing airflow recirculation inside a fan cover by a centrifugal fan.

[0002] For industrial electric motors that operate in both directions of rotation rather than unidirectionally, axial or diagonal fans cannot be used as cooling fans, and centrifugal fans must be used.

[0003] Figure 1 shows the cooling structure of a conventional industrial electric motor. In the exploded perspective view shown in Figure 1, the frame cover (front) to the frame cover (rear) are the components of the industrial electric motor, and the cooling fan and fan cover are components for cooling the motor. As previously mentioned, when the motor is operated in both directions, a centrifugal fan is used as the cooling fan. A centrifugal fan is a fan that draws in air and then deflects it 90 degrees by centrifugal force to radially discharge it to the side.

[0004] Figure 2 shows a centrifugal fan that is widely used in conventional industrial electric motors. The centrifugal fan changes the direction of air entering through the grille (mesh) of the fan cover to a centrifugal direction and causes it to flow through the frame cover (rear) and the frame, thereby air-cooling the electric motor.

[0005] However, a recirculation flow may occur in which some of the air deflected in the centrifugal direction by the rotation of the centrifugal fan moves upstream along the surface of the fan cover and flows back into the centrifugal fan. Recirculation flow is a phenomenon in which a portion of the airflow continues to circulate inside the fan cover. Figure 3 shows the recirculation flow phenomenon occurring inside the fan cover (indicated by a rectangle) by the centrifugal fan.

[0006] The present invention has been devised to solve the above-mentioned problems, and the objective of the present invention is to provide a cooling structure for a bidirectional motor utilizing a variable guide vane installed on the fan cover of a centrifugal fan, as a method to improve cooling efficiency by reducing the recirculation flow generated inside the fan cover by the centrifugal fan used for cooling the bidirectional motor and increasing the cooling flow rate delivered to the motor.

[0007] A motor system according to one embodiment of the present invention for achieving the above objective comprises: a motor rotatable in both directions; a centrifugal fan that rotates in conjunction with the motor for cooling the motor; a fan cover surrounding the centrifugal fan; and variable guide vanes disposed on the outer edge of the fan inside the centrifugal fan cover, the torsional angle of which varies.

[0008] Variable guide vanes can form a helical flow guide by twisting, thereby guiding the recirculating flow generated inside the fan cover toward the outlet.

[0009] Variable guide vanes can be torsionally connected, with one end connected to a fan cover and the other end connected to a rotor that rotates along the circumference of the fan cover.

[0010] Variable guide vanes can be made of a material that is elastic in the longitudinal direction.

[0011] The electric motor system according to the present invention may further include an actuator that adjusts the rotational direction of a rotor; and a controller that detects the rotational direction of the electric motor, determines the rotational direction of the rotor according to the detected rotational direction of the electric motor, and controls the actuator according to the determined rotational direction of the rotor.

[0012] If the rotation direction of the motor is clockwise, the controller rotates the rotor by a predetermined angle in the first direction to change the twist angle of the variable guide vanes to the first angle, and if the rotation direction of the motor is counterclockwise, the controller rotates the rotor by a predetermined angle in the second direction to change the twist angle of the variable guide vanes to the second angle.

[0013] The first angle and the second angle may have the same size but opposite directions.

[0014] When the controller detects that the rotation direction of the motor has changed, it determines the rotation direction of the rotor according to the changed rotation direction of the motor and can control the actuator according to the determined rotation direction of the rotor.

[0015] The controller can further detect the rotational speed of the motor, further determine the amount of rotation of the rotor according to the detected rotational speed of the motor, and further control the actuator according to the determined amount of rotation of the rotor.

[0016] According to another aspect of the present invention, a method for controlling motor cooling is provided, comprising the steps of: driving a motor rotatable in both directions; detecting the rotational direction of the motor; determining the rotational direction of a rotor based on the detected rotational direction; rotating the rotor according to the determined rotational direction; and changing the torsional angle of guide vanes disposed on the outer edge of a fan inside a fan cover surrounding a centrifugal fan that rotates in conjunction with the motor for cooling the motor, through rotation.

[0017] According to another aspect of the present invention, a cooling system for an electric motor is provided, comprising: a centrifugal fan that rotates in conjunction with the electric motor for cooling a bidirectionally rotatable electric motor; a fan cover surrounding the centrifugal fan; guide vanes disposed on the outer edge of the fan inside the centrifugal fan cover, with one end connected to the fan cover in a torsionable state; a rotor that rotates along the circumference of the fan cover, with the other end of the guide vanes connected in a torsionable state; an actuator that adjusts the rotational direction of the rotor; and a controller that detects the rotational direction of the electric motor, determines the rotational direction of the rotor according to the detected rotational direction of the electric motor, and controls the actuator according to the determined rotational direction of the rotor.

[0018] According to another aspect of the present invention, a method for controlling motor cooling is provided, comprising: a step of detecting the rotational direction of a motor rotatable in both directions; a step of determining the rotational direction of a rotor based on the detected rotational direction; a step of rotating the rotor according to the determined rotational direction; and a step of changing the twist angle of guide vanes disposed on the outer edge of a fan inside a fan cover surrounding a centrifugal fan that rotates in conjunction with the motor for cooling the motor, through rotation.

[0019] As described above, according to the embodiments of the present invention, a variable guide vane is installed on the fan cover of a centrifugal fan to be used for cooling a bidirectional electric motor, and the twist angle is adjusted according to the direction of rotation, thereby reducing the recirculation flow generated inside the fan cover by the centrifugal fan, which increases the cooling flow rate delivered to the electric motor and improves cooling efficiency.

[0020] According to embodiments of the present invention, by improving the cooling efficiency of a bidirectional electric motor, the size of the centrifugal fan for cooling can be reduced, the secondary cooling equipment can be simplified, and mechanical loss can be reduced from the perspective of the overall industrial electric motor system, thereby increasing the efficiency and lifespan of the electric motor.

[0021] FIG. 1 shows the cooling structure of a conventional industrial electric motor,

[0022] Figure 2 shows a centrifugal fan widely used in conventional industrial electric motors,

[0023] Figure 3 shows the recirculation flow phenomenon occurring inside the fan cover by a centrifugal fan,

[0024] FIG. 4 is a diagram illustrating the configuration of an industrial electric motor system according to an embodiment of the present invention.

[0025] FIGS. 5 and FIGS. 6 are drawings illustrating the actual structure of the fan cover.

[0026] FIGS. 7 and FIGS. 8 are drawings illustrating the state of the fan cover when the rotor rotates clockwise.

[0027] FIGS. 9 and FIGS. 10 are drawings illustrating the state of the fan cover when the rotor rotates counterclockwise.

[0028] FIG. 11 is a diagram illustrating the flow of an industrial electric motor cooling control method according to another embodiment of the present invention.

[0029] The present invention will be described in more detail below with reference to the drawings.

[0030] An embodiment of the present invention presents a cooling structure for a bidirectional electric motor utilizing a variable guide vane installed on the fan cover of a centrifugal fan. This technology involves installing a variable guide vane on the fan cover of a centrifugal fan, which is used for cooling the bidirectional electric motor, and adjusting the twist angle according to the direction of rotation to guide the recirculating flow generated within the fan cover by the centrifugal fan in a spiral toward the outlet direction.

[0031] FIG. 4 is a diagram illustrating the configuration of an industrial motor system according to an embodiment of the present invention. As illustrated, the industrial motor system according to an embodiment of the present invention comprises a bidirectional motor (110), a centrifugal fan (120), a fan cover (130), an actuator (140), and a controller (150).

[0032] The bidirectional motor (110) is a motor that can rotate in both directions and can change its direction of rotation during operation, and can be composed of the components from the frame cover (front) to the frame cover (rear) of FIG. 1 described above.

[0033] The centrifugal fan (120) is configured for cooling the bidirectional motor (110) and draws in air from the grille (131) of the fan cover (130) and flows it toward the outlet side where the bidirectional motor (110) is located. Since the centrifugal fan (120) rotates in conjunction with the rotation axis of the bidirectional motor (110), the rotation direction of the centrifugal fan (120) coincides with the rotation direction of the bidirectional motor (110). Accordingly, when the rotation direction of the bidirectional motor (110) changes from clockwise to counterclockwise, the rotation direction of the centrifugal fan (120) also changes from clockwise to counterclockwise. Likewise, when the rotation direction of the bidirectional motor (110) changes from counterclockwise to clockwise, the rotation direction of the centrifugal fan (120) also changes from counterclockwise to clockwise.

[0034] The fan cover (130) is a cover surrounding the centrifugal fan (120), which protects the centrifugal fan (120) from the external environment, and has a grid-shaped grille (131) formed on the front for air intake.

[0035] FIG. 5 illustrates the actual structure of the fan cover (130), and FIG. 6 illustrates the fan cover (130) shown in FIG. 5 viewed from various angles. As illustrated, the fan cover (130) has a cylindrical shape in which a centrifugal fan (120) can be housed, a grille (131) is formed on the front, guide vanes (133) are installed inside, and a rotor (132) is rotatably coupled to the air outlet side.

[0036] Guide vanes (133) are positioned on the outer edge of a centrifugal fan (not shown) inside a fan cover (130). One end of the guide vanes (133) is connected to the fan cover (130), and the other end is connected to a rotor (132).

[0037] The rotor (132) is rotatably coupled to the circumferential portion of the air outlet side of the fan cover (130). By doing so, the rotor (132) is rotatable on the air outlet side of the fan cover (130). FIGS. 7 and 8 illustrate the state of the fan cover (130) when the rotor (132) is rotated clockwise, and FIGS. 9 and 10 illustrate the state of the fan cover (130) when the rotor (132) is rotated counterclockwise.

[0038] As illustrated in FIGS. 7 to 10, when the rotor (132) rotates, the twist angle of the guide vanes (133) changes. This is because one end of the guide vanes (133) is fixed to the fan cover (130), while the other end is fixed to the rotor (132) that rotates relative to the fan cover (130).

[0039] Depending on the rotation direction of the rotor (132), the twist angle of the guide vanes (133) is opposite. For example, when the rotor (132) rotates clockwise by a certain angle, the twist angle of the guide vanes (133) and when the rotor (132) rotates counterclockwise by a certain angle have the same magnitude but opposite signs. That is, the sum of the twist angles in each of the two rotation states is 0. To enable twisting when the rotor (132) rotates, the guide vanes (133) are made of a material that is elastic in the longitudinal direction, for example, rubber.

[0040] Referring again to FIG. 4, the explanation is as follows: The actuator (140) is an actuator that rotates the rotor (132) by a predetermined angle in a clockwise or counterclockwise direction. The direction of rotation of the rotor (132) by the actuator (140) is controlled by the controller (150).

[0041] The controller (150) detects the rotation direction of the bidirectional motor (110) and controls the rotation direction of the rotor (132) according to the detected rotation direction. The rotation direction of the bidirectional motor (110) may be detected by adding a sensor, such as a Hall sensor, but it is also possible to detect it through the voltage / current relationship of the bidirectional motor (110) or by linking with the controller / PLC (not shown) of the bidirectional motor (110).

[0042] If the rotation direction of the bidirectional motor (110) is clockwise, the controller (150) rotates the rotor (132) clockwise to change the twist angle of the guide vanes (133) as shown in FIG. 7. On the other hand, if the rotation direction of the bidirectional motor (110) is counterclockwise, the controller (150) rotates the rotor (132) counterclockwise to change the twist angle of the guide vanes (133) as shown in FIG. 9.

[0043] When the rotation direction of the rotor (132) is controlled by the controller (150), the twist angle of the guide vanes (133) is also changed, and the spiral flow guide formed by the guide vanes (133) with the changed twist angle guides the recirculating flow occurring inside the fan cover (130) toward the outlet direction.

[0044] Guide vanes are wing devices that reduce flow resistance and guide the fluid flow in a desired direction. In the embodiment of the present invention, by creating an inlet and outlet of the fluid flow through the installation of guide vanes (133), the recirculation area is reduced and flow transition is reduced, thereby allowing the flow resistance of the overall system to be reduced and the efficiency to be increased. That is, when using a centrifugal fan (120) as a cooling fan that considers bidirectional rotation, unlike the recirculation flow that generally occurs while flowing along the smooth fan cover (130) inside, the flow is made to flow toward the outlet of the fan cover (130) through the guide vanes (133).

[0045] FIG. 11 is a diagram illustrating the flow of an industrial electric motor cooling control method according to another embodiment of the present invention.

[0046] As described above, when the bidirectional motor (110) is driven (S210), the centrifugal fan (120) rotates in conjunction with it (S220). Then, to cool the bidirectional motor (110), the controller (150) first detects the rotation direction of the bidirectional motor (110) (S230).

[0047] The next controller (150) determines the rotation direction of the rotor (132) based on the rotation direction detected in step S220 (S240), and rotates the rotor (132) according to the determined rotation direction (S250).

[0048] Specifically, if the rotation direction of the bidirectional motor (110) detected in step S220 is clockwise, the rotation direction of the centrifugal fan (120) determined in step S230 is also clockwise, and if the rotation direction of the bidirectional motor (110) detected in step S220 is counterclockwise, the rotation direction of the centrifugal fan (120) determined in step S230 is counterclockwise.

[0049] By rotating the rotor (132) in step S240, the twist angle of the guide vanes (133) is set so that the recirculating flow generated inside the fan cover (130) is guided toward the outlet (S260).

[0050] Subsequently, the controller (150) detects a change in the rotation direction of the bidirectional motor (110) (S270). If a change in the rotation direction is detected (S260-Y), the process is repeated from step S230 to change the rotation direction of the rotor (132) and change the twist angle of the guide vanes (133) (S230 to S260).

[0051] Up to now, a cooling structure for a bidirectional electric motor utilizing a variable guide vane installed on the fan cover of a centrifugal fan has been described in detail with reference to a preferred embodiment.

[0052] In the above embodiment, a variable guide vane is installed on the fan cover of a centrifugal fan to be used for cooling a bidirectional motor, and the twist angle is adjusted according to the direction of rotation. By reducing the recirculation flow generated inside the fan cover by the centrifugal fan, the cooling flow rate delivered to the motor is increased, thereby improving cooling efficiency.

[0053] In addition, by improving the cooling efficiency of the bidirectional motor, the size of the centrifugal cooling fan can be reduced, the secondary cooling equipment can be simplified, and mechanical losses can be reduced from the perspective of the overall industrial motor system, thereby increasing the motor efficiency and lifespan.

[0054] Meanwhile, in the above embodiment, the controller (150) detects only the rotational direction of the bidirectional motor (110) and controls only the rotational direction of the rotor (132), thereby changing only the twisting direction of the guide vanes (133).

[0055] However, it is also possible to extend the controller (150) to detect the rotational speed of the bidirectional motor (110) and control the amount of rotation in addition to the rotational direction of the rotor (132), thereby changing the degree of twisting in addition to the twisting direction of the guide vanes (133).

[0056] Meanwhile, it goes without saying that the technical concept of the present invention may also be applied to a computer-readable recording medium containing a computer program that enables the device and method according to the present embodiment to perform their functions. Furthermore, the technical concept according to various embodiments of the present invention may be implemented in the form of computer-readable code recorded on a computer-readable recording medium. A computer-readable recording medium may be any data storage device that can be read by a computer and store data. For example, a computer-readable recording medium may be a ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical disk, hard disk drive, etc. Additionally, computer-readable code or a program stored on a computer-readable recording medium may be transmitted through a network connected between computers.

[0057] Furthermore, although preferred embodiments of the present invention have been illustrated and described above, the present invention is not limited to the specific embodiments described above. Various modifications are possible by those skilled in the art without departing from the essence of the invention as claimed in the claims, and such modifications should not be understood individually from the technical spirit or perspective of the present invention.

Claims

1. Electric motor capable of rotating in both directions; A centrifugal fan that rotates in conjunction with the motor for cooling the motor; Fan cover surrounding the centrifugal fan; An electric motor system characterized by including variable guide vanes that are positioned on the outer edge of the fan inside the centrifugal fan cover and whose twist angle is variable.

2. In Claim 1, Variable guide vanes are, An electric motor system characterized by forming a spiral flow guide by twisting to guide the recirculating flow generated inside the fan cover toward the outlet.

3. In Claim 2, Variable guide vanes are, An electric motor system characterized by having one end connected to a fan cover and the other end connected to a rotor that rotates along the circumference of the fan cover, in a torsionable state.

4. In Claim 3, Variable guide vanes are, An electric motor system characterized by being made of a material that is elastic in the longitudinal direction.

5. In Claim 3, Actuator for adjusting the rotational direction of a rotary device; A motor system characterized by further including a controller that detects the rotational direction of a motor, determines the rotational direction of a rotor according to the detected rotational direction of the motor, and controls an actuator according to the determined rotational direction of the rotor.

6. In Claim 5, The controller is, If the rotation direction of the motor is clockwise, the rotor is rotated in the first direction by a predetermined angle, and the twist angle of the variable guide vanes is changed to the first angle, and A motor system characterized by, when the rotation direction of the motor is counterclockwise, rotating the rotor by a predetermined angle in a second direction to change the twist angle of the variable guide vanes to a second angle.

7. In Claim 6, The first angle and the second angle are, An electric motor system characterized by having the same size and opposite direction.

8. In Claim 5, The controller is, A motor system characterized by detecting that the rotation direction of the motor has changed, determining the rotation direction of the rotor according to the changed rotation direction of the motor, and controlling the actuator according to the determined rotation direction of the rotor.

9. In Claim 5, The controller is, An electric motor system characterized by further detecting the rotational speed of the electric motor, further determining the amount of rotation of the rotor according to the detected rotational speed of the electric motor, and further controlling the actuator according to the determined amount of rotation of the rotor.

10. A step of driving a motor rotatable in both directions; A step of detecting the rotational direction of the electric motor; A step of determining the rotation direction of the rotor based on the detected rotation direction; A step of rotating the rotor according to the determined rotation direction; A motor cooling control method characterized by including the step of changing, through rotation, the twist angle of guide vanes arranged on the outer edge of a fan inside a fan cover surrounding a centrifugal fan that rotates in conjunction with the motor for cooling the motor.

11. A centrifugal fan that rotates in conjunction with the motor for cooling a bidirectionally rotatable motor; Fan cover surrounding the centrifugal fan; Guide vanes positioned on the outer edge of the fan from the inside of the centrifugal fan cover, with one end connected to the fan cover in a torsionable state; A rotary device that rotates along the circumference of a fan cover and has the other end of a guide vane connected in a torsional state; Actuator for adjusting the rotational direction of a rotary device; A cooling system for an electric motor characterized by including a controller that detects the rotational direction of the electric motor, determines the rotational direction of the rotor according to the detected rotational direction of the electric motor, and controls the actuator according to the determined rotational direction of the rotor.

12. A step of detecting the rotational direction of a bidirectionally rotatable electric motor; A step of determining the rotation direction of the rotor based on the detected rotation direction; A step of rotating the rotor according to the determined rotation direction; A motor cooling control method characterized by including the step of changing, through rotation, the twist angle of guide vanes arranged on the outer edge of a fan inside a fan cover surrounding a centrifugal fan that rotates in conjunction with the motor for cooling the motor.

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