TURBO FAN AND CEILING TYPE AIR CONDITIONER USING THEREOF

Abstract

A turbo fan includes a main plate rotated by power provided from a fan motor, blades each having one end connected to the main plate to perform rotation movement, and a shroud having an inner circumferential part and an outer circumferential part, an other end of each of the blades connected to the shroud. The shroud includes a plurality of curved parts each having one side connected to the inner circumferential part and an other side connected to the outer circumferential part, the plurality of curved parts each having a predetermined curvature.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 119 and 35 U.S.C. 365 to Korean Patent Application No. 10-2013-0043388 (filed on Apr. 19, 2013), which is hereby incorporated by reference in its entirety.

BACKGROUND

The present disclosure relates to a turbo fan and a ceiling type air conditioner using the same.

In general, ceiling type air conditioners are devices that are positioned in an indoor ceiling to discharge heat-exchanged air into an indoor space after suctioning indoor air from the ceiling. In such a ceiling type air conditioner, air is suctioned through a suction hole defined in a central portion of the ceiling type air conditioner, and then, the suctioned air is heat-exchanged by a heat exchanger disposed within the ceiling type air conditioner. The air-conditioned air may be discharged into the indoor space through a discharge part disposed on a circumferential portion of the ceiling type air conditioner to adjust a temperature and moisture of the indoor space.

Particularly, the air suctioned through the suction hole may be guided in movement by a turbo fan disposed within the ceiling type air conditioner. That is, the turbo fan may suction air in an axial direction with respect to the turbo fan and discharge in a radius direction of the turbo fan.

FIG. 1 is a perspective view of a turbo fan according to a related art.

Referring to FIG. 1, a turbo fan 1 according to a related art may include a main plate 10 rotating by power provided from a motor, a plurality of blades 20 radially arranged on the main plate 10 and integrated with the main plate 10, and a shroud 30 coupled to ends of the blades 20 to face one surface of the main plate 10.

Also, the turbo fan 1 may further include a hub 11 accommodating the motor therein, a boss part 12 having a shaft hole in a central portion of the hub 11 so that the motor is shaft-coupled to the shaft hole, and a vent part 13 defined in a surface of the hub 11 to cool the motor. The vent part 13 may introduce cold air into the motor therethrough to decrease a temperature of the motor.

The shroud 30 may have an inner circumference 31 and an outer circumference 32 so that air is introduced into the turbo fan 1 and then discharged radially. A suction hole 33 suctioning air may be defined in a central portion of the shroud 30. Also, a discharge hole 34 discharging the suctioned air may be defined in a circumferential direction between the main plate 10 and the shroud 30.

According to the related art, air suctioned into the turbo fan 1 through the suction hole 33 may be discharged to the outside of the turbo fan 1 through the discharge hole 34. The discharge hole 34 may be defined as a space between the shroud 30 and the main plate 10.

However, when the ceiling type air conditioner is changed in operation mode or operates for a long time, an amount of air introduced into the turbo fan 1 through the suction hole may gradually increase. Thus, when the suctioned air is discharged to the outside through the discharge hole 34, a large amount of air may be discharged through a predetermined area to cause air flow noises.

SUMMARY

Embodiments provide a turbo fan which reduces air flow noises when air suctioned therein is discharged to the outside thereof and a ceiling type air conditioner using the same.

In one embodiment, a turbo fan includes: a main plate rotated by power provided from a fan motor; blades each having one end connected to the main plate to perform rotation movement; and a shroud having an inner circumferential part and an outer circumferential part, an other end of each of the blades connected to the shroud, wherein the shroud includes: a plurality of curved parts each having one side connected to the inner circumferential part and an other side connected to the outer circumferential part, the plurality of curved parts each having a predetermined curvature.

In another embodiment, a ceiling type air conditioner includes: a case defining an outer appearance; a fan motor disposed within the case; a turbo fan disposed within the case to change a moving direction of air passing through the suction hole; and a heat exchanger disposed outside the turbo fan, wherein the turbo fan including: a main plate rotated by power provided from the fan motor; blades each having one end connected to the main plate to perform rotation movement; and a shroud having an inner circumferential part and an outer circumferential part, an other end of each of the blades connected to the shroud, wherein the shroud includes: a plurality of curved parts each having one side connected to the inner circumferential part and an other side connected to the outer circumferential part, the plurality of curved parts each having a predetermined curvature.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a turbo fan according to a related art.

FIG. 2 is a perspective view illustrating an indoor unit of a ceiling type air conditioner according to an embodiment.

FIG. 3 is a cross-sectional view illustrating the indoor unit of the ceiling type air conditioner according to an embodiment.

FIG. 4 is a perspective view of a turbo fan according to an embodiment.

FIG. 5 is a plan view of the turbo fan according to an embodiment.

FIG. 6 is a front view of the turbo fan according to an embodiment.

FIG. 7 is a schematic view illustrating a flow of air passing through the ceiling type air conditioner according to an embodiment.

FIG. 8 is a graph illustrating a relationship between an air volume and a noise when the turbo fan according to an embodiment is applied to the ceiling type air conditioner.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings.

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific preferred embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is understood that other embodiments may be utilized and that logical structural, mechanical, electrical, and chemical changes may be made without departing from the spirit or scope of the invention. To avoid detail not necessary to enable those skilled in the art to practice the invention, the description may omit certain information known to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense.

FIG. 2 is a perspective view illustrating an indoor unit of a ceiling type air conditioner according to an embodiment, and FIG. 3 is a cross-sectional view illustrating the indoor unit of the ceiling type air conditioner according to an embodiment.

Referring to FIGS. 2 and 3, a ceiling type air conditioner according to an embodiment may include an outdoor unit (not shown) installed in an outdoor space, an indoor unit 100 installed in an indoor space, and a refrigerant tube (not shown) connecting the outdoor unit (not shown) to the indoor unit 100 to allow a refrigerant to flow therethrough.

The indoor unit 100 may include a case 105 defining an outer appearance thereof, a turbo fan 200 disposed within the case 105, a fan motor 120 coupled to the turbo fan 200 to provide power, and a heat exchanger 130 disposed outside the fan motor 120.

The case 105 may include a main body 101 defining side surfaces thereof and a front panel 102 coupled to the main body 101 to define a front surface thereof.

Also, the main body 101 is installed in an indoor ceiling. The main body 101 may have an opened lower portion to communicate with a suction hole 150 defined in the front surface of the front panel 102. Although the main body 101 is installed in the indoor ceiling in consideration of space availability or a sense of beauty, the installed location of the main body 101 is not limited thereto. For example, the main body 101 may be installed in an indoor sidewall.

The front panel 102 may be detachably coupled to the lower portion of the main body 101. Also, the front panel 102 may be exposed to the indoor space so that air is suctioned into or discharged from the indoor unit 100. The front panel 102 may cover the opened portion of the main body 101. For example, the front panel 102 may have a square plate shape to cover the opening of the main body 101. Also, the front panel 102 may include a suction hole 150 through which indoor air is suctioned and a discharge hole 140 through which air is discharged into the indoor space.

The suction hole 150 may be defined in a central portion of the front panel 102. The discharge holes 140 may be symmetrically defined in four sides surrounding the suction hole 150. The suction hole 150 may have a grill structure. Each of the discharge holes 140 may have a rectangular structure with a predetermined width and length. However, each of the suction hole 150 and the discharge holes 140 are not limited to a shape thereof.

Also, a filter 190 for removing various foreign substances contained in the air suctioned into the main body 101 through the suction hole 150 may be provided inside the front panel 102.

The turbo fan 200 may include a hub 112 connected to a rotation shaft of the fan motor 120, a main plate 115 rotated by the fan motor 120, a plurality of blades 400 having one ends connected to the main plate 115 and arranged at a predetermined distance along a circumferential direction on the main plate 115, and a shroud 300 facing the main plate 115 to connect the other ends of the plurality of blades 400 to the shroud 300. The shroud 300 may guide an inflow of air into the suction hole 150 when the turbo fan 200 rotates.

The shroud 300 may include a plurality of mountain parts 330 protruding upward from one surface of the shroud 300 and a plurality of valley parts 340 disposed between the plurality of mountain parts 330. That is, the shroud 300 may have a three-dimensional shape.

The turbo fan 200 may be disposed on a position corresponding to the suction hole 150 to improve suction efficiency of the air suctioned into the main body 101. Particularly, as shown in FIG. 3, the turbo fan 200 may be disposed to correspond to a vertical direction of the suction hole 150.

Also, the turbo fan 200 may blow the indoor air suctioned through the suction hole 150 toward the heat exchanger 130.

The heat exchanger 130 may surround the outside of the turbo fan 200. For example, the heat exchanger 130 may have a square structure corresponding to a shape of each of the side surfaces of the main body 101. The heat exchanger 130 may heat-exchange with the air suctioned into the main body 101 through the turbo fan 200. Particularly, when the ceiling type air conditioner operates in a cooling mode, air passing through the heat exchanger 130 may decrease in temperature. On the other hand, when the ceiling type air conditioner operates in a heating mode, air passing through the heat exchanger 130 may increase in temperature.

A drain plate 131 accommodating condensed water generated when the refrigerant passing through the heat exchanger 130 is heat-exchanged with the indoor air may be disposed under the heat exchanger 130. Also, a drain tube (not shown) for discharging the condensed water collected in the drain plate 131 to the outside may be connected to the drain plate 131.

A guide passage 181 for guiding a flow direction of air may be defined in an outer portion of the inside of the main body 101. Particularly, the guide passage 181 may guide the air heat-exchanged with the heat exchanger 130 toward the discharge hole 140.

A vane 141 for controlling the flow direction of the air may be disposed in the discharge hole 140. The vane 141 may be rotatable at a predetermined angle. Also, the vane 141 may be inclined outward from the front surface of the front panel 102. This is done for providing air having a uniform wind speed to all indoor portions. However, the rotation direction of the vane 141 is not limited thereto. Also, the vane 141 is not limited to an arrangement, configuration, and operation method as described thereof.

Hereinafter, a detailed structure of the turbo fan 200 will be described.

FIG. 4 is a perspective view of a turbo fan 200 according to an embodiment, FIG. 5 is a plan view of the turbo fan according to an embodiment, and FIG. 6 is a front view of the turbo fan according to an embodiment.

Referring to FIGS. 4 to 6, the turbo fan 200 according to an embodiment may include a main plate 115 rotated by a power provided from a fan motor, a hub 112 accommodating the fan motor therein, a plurality of blades 400 having one ends connected to the main plate 115 and arranged radially on the main plate 115, and a shroud 300 connecting the other end of each of the plurality of blades 400 to the shroud 300 to guide a flow direction of air.

The hub 112 may include a boss part 220 shaft-coupled to the fan motor disposed at a central portion of the hub 112 and a vent part 210 providing a moving path of air. The vent part 210 may introduce cold air into the motor therethrough to decrease a temperature of the motor.

Each of the blades 400 may include a blade front end 420 disposed adjacent to the hub 112 and a blade rear end 410 spaced apart from the hub 112 to guide air flowing along the blades 400 to a heat exchanger (see reference numeral 130 of FIG. 3).

A hollow portion providing a moving path of air may be defined in a central portion of the shroud 300. That is, an air suction part 360 may be disposed in the hollow portion so that indoor air is suctioned into the turbo fan 200. The air suctioned through the air suction part 360 may be discharged to the outside through an exhaust part 450 defined in a space between the plurality of blades 400.

The shroud 300 may include an inner circumferential part 370 defining an inner circumferential surface of the shroud 300 and disposed adjacent to the air suction part 360 and an outer circumferential part 380 defining an outer circumferential surface of the shroud 300 and disposed adjacent to the exhaust part 450.

Also, the shroud 300 may include a guide part 310 disposed adjacent to the inner circumferential part 370 to guide a flow direction of air and a curved part 320 connected to the guide part 310 and having a predetermined curvature. Particularly, the guide part 310 may guide a flow direction of air introduced into the turbo fan 200 through the suction part 360. The curved part 320 may guide a flow of air so that the air guided into the turbo fan 200 through the guide part 310 is discharged to the outside through the exhaust part 450.

The curved part 320 may be provided in plurality. Also, the plurality of curved part 320 may include a mountain part 330 disposed spaced away from the main plate 115 and a valley part 340 disposed spaced closer to the main plate 115 than the mountain part 330. The curved part 320 may include a first curved part 321 and a second curved part 322 disposed adjacent to the first curved part 321. Also, the valley part 340 may be disposed on a boundary surface between the first curved part 321 and the second curved part 322.

The curved part 320 may further include an inclined part 350 connecting the mountain part 330 to the valley part 340. The inclined part 350 may be defined as a surface connecting the mountain part 330 to the valley part 340, a surface connecting the mountain part 330 to the outer circumferential part 380, and a surface connecting the mountain part 310 to the guide part 310.

Also, a surface on which the blades 400 and the shroud 300 meet may have a curvature radius less than that of the valley part 340. That is, the valley part 340 may have a length greater than a length of the surface on which the blade 400 and the shroud 300 meet. This is done for smoothly guiding a flow of air into the exhaust part 450.

When a point at which the outer circumferential part 380 of the shroud 300 and the blade 400 meet is referred to as a first contact 430, and a point at which the outer circumferential part 380 of the shroud 300 and the next blade 400 meet, the point being disposed adjacent to the first contact 430, is referred to as a second contact 440, a space within the exhaust part 450 may be partitioned by an extension part 460 connecting the first contact 430 to the second contact 440.

Particularly, the extension part 460 may be defined as a virtual line connecting the first contact 430 to the second contact 440. The exhaust part 450 may include a first exhaust part 451 disposed at an upper side with respect to the extension part 460 and a second exhaust part 452 disposed at a lower side with respect to the extension part 460.

According to the related art, the turbo fan may include one exhaust part. However, the turbo fan 200 according to an embodiment may further include the first exhaust part 451 because the outer circumferential part 380 of the shroud 300 having a predetermined curvature and the second exhaust part 452. Thus, air introduced into the turbo fan 200 may be discharged to the outside through the first exhaust part 451 as well as the second exhaust part 452 increasing an air flow space, compared to the turbo fan of the related art, thereby reducing air flow noises.

The turbo fan 200 according to an embodiment may further include a rotation shaft (not shown) providing a rotation center of the main plate 115. If a central line (not shown) is a virtual line defined when the rotation shaft (not shown) and the virtual line extending through the mountain part 330 extend in parallel, with respect to the central line (not shown), a distance between the mountain part 330 and the inner circumferential part 370 may be greater than a distance between the mountain part 330 and the outer circumferential part 380. That is, with respect to a flow direction of air passing through the shroud 300, a flow space of air introduced into the shroud 300 may be less than that of air discharged from the shroud 300.

Thus, the air passing through the shroud 300 may more smoothly flow. Also, a pressure loss of the air passing through the shroud 300 may be reduced.

With respect to the outer circumferential part 380, a point disposed spaced furthest away from the main plate 115 may be defined as a protrusion 381. When a distance between the protrusion 381 and the extension part 460 is a, and a distance between the extension part 460 and the main plate 115 is b, a value of a/b may be greater than about 0.05 and less than about 0.05. That is, a distance between the first exhaust part 451 and the extension part 460 and a distance between the second exhaust part 452 and the extension part 460 may be decided according to a predetermined ratio.

Also, when a length of the extension part 460 is c, a value of a/c may be greater than about 0.02 and less than about 0.06. That is, the distance between the first exhaust part 451 and the extension part 460 and the length of the extension part 460 may be decided according to a predetermined ratio.

However, the present disclosure is not limited to the values of a, b, and c and the ratios among a, b, and c. For example, more various embodiments may be applied to the current embodiment.

Hereinafter, an operation process of the ceiling type air conditioner according to an embodiment will be described.

FIG. 7 is a schematic view illustrating a flow of air passing through the ceiling type air conditioner according to an embodiment.

FIG. 7 illustrates a flow of air on the basis of the structure of FIG. 3. Thus, the same structure as that of FIG. 3 will be expressed as the same reference numeral.

Referring to FIG. 7, when the ceiling type air conditioner according to an embodiment operates, the indoor unit 100 connected to the outdoor unit (not shown) may operate. When the indoor unit 100 operates, the main plate 115 may rotate by driving of the fan motor 120. As the main plate 115 rotates, the plurality of blades 400 connected to the main plate 115 may also rotate. When the plurality of blades 400 rotate, indoor air may be suctioned through the suction hole 150 defined in the center of the front panel 102 of the indoor unit 100. The suctioned air may pass through the filter 190 to filter foreign substances. Also, a flow of the suction air may be guided into the turbo fan 200 by the shroud 300. Particularly, the air may be suctioned into the turbo fan 200 through the air suction part 360 that is a space defined by the inner circumferential part 370 of the shroud 300.

The air introduced into the turbo fan 200 may be radially discharged by the rotation of the plurality of blades 400. That is, the air introduced into a lower portion of the turbo fan 200 may be discharged in a lateral direction by the operation of the turbo fan 200.

The shroud 300 may include a plurality of curved parts 320. The plurality of curved parts 320 may include a plurality of mountain parts 330, a plurality of valley parts 340, and an inclined part 350 connecting each of the mountain part 330 to each of the valley parts 340. The inclined part 350 may include the protrusion 381 protruding from the extension part in one direction. Thus, the air suctioned into the turbo fan 200 may be discharged to the outside along the first exhaust part 451 defined by the protrusion 381 and the second exhaust part 452 communicating with the first exhaust part 451.

A portion of air discharged from the blades may pass through the heat exchanger 130 and then be heat-exchanged with a refrigerant flowing into the heat exchanger 130. The heat-exchanged refrigerant may be discharged into the indoor space through the discharge hole 140. Also, the plurality of vanes 141 may be disposed in the discharge hole 140 to adequately condition the indoor space.

FIG. 8 is a graph illustrating a relationship between an air volume and noise when the turbo fan according to an embodiment is applied to the ceiling type air conditioner.

Referring to FIG. 8, when the ceiling type air conditioner to which the shroud according to the related art is applied operates, the more an air volume increases, the more the noise may increase (M). On the other hand, when the ceiling type air conditioner to which the shroud according to the current embodiment is applied operates, the more an air volume increases, the more the noise may relatively slightly increase (N) when compared to that of the related art (M).

The shroud 300 according to the current embodiment may include the plurality of mountain parts 330, the plurality of valley parts 340, and the inclined part 350 connecting each of the mountain part 330 to each of the valley parts 340. Thus, the plurality of exhaust parts 450 may be defined in the turbo fan 200 by the plurality of mountain parts 330, the plurality of valley parts 340, and the inclined part 350. That is, in the turbo fan 200 according to the current embodiment, since the exhaust part 450 has a relatively wide area when compared to the related art, the air flow space may increase. Thus, the flow noise of the air passing through the exhaust part 450 may be reduced, and it may prevent an inner air pressure of the exhaust part 450 from suddenly increasing.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Claims

1. A turbo fan comprising:

a main plate rotated by power provided from a fan motor;

a plurality of blades, each blade having one end connected to the main plate to perform rotation movement; and

a shroud having an inner circumferential part and an outer circumferential part, an other end of each of the blades connected to the shroud,

wherein the shroud comprises:

a plurality of curved parts, each curved part having one side connected to the inner circumferential part and an other side connected to the outer circumferential part, the plurality of curved parts each having a predetermined curvature.

2. The turbo fan according to claim 1, wherein at least one of the plurality of curved parts comprises a mountain part spaced away from the main plate.

3. The turbo fan according to claim 2, wherein the plurality of curved parts comprise a first curved part and a second curved part disposed adjacent to the first curved part,

a valley part disposed on a boundary surface between the first curved part and the second curved part, the valley part being disposed spaced closer to the main plate than the mountain part; and

an inclined part connecting the mountain part to the valley part, the inclined part having the predetermined curvature.

4. The turbo fan according to claim 3, wherein each of the plurality of curved parts comprises the mountain part, and the mountain part and the valley part are alternately disposed with respect to each other along a circumferential direction of the shroud.

5. The turbo fan according to claim 2, further comprising:

a rotation shaft providing a rotation center of the main plate, and

a central line that is a virtual line defined when the rotation shaft and the virtual line extending through mountain part extend in parallel, wherein a distance between the mountain part and the inner circumferential part is greater than a distance between the mountain part and the outer circumferential part with respect to the central line.

6. The turbo fan according to claim 2, wherein an angle of a slope of a surface connecting the mountain part to the inner circumferential part is less than a slope of a surface connecting the mountain part to the outer circumferential part.

7. The turbo fan according to claim 1, wherein a first contact is a point at which the outer circumferential part and a blade meet, and a second contact is a point at which the outer circumferential part and an adjacent blade meet, the extension part defined as a virtual line connecting the first contact point and the second contact point. and a protrusion is a point at the outer circumferential part disposed spaced furthest away from the main plate,

wherein when a distance between the protrusion and the extension part is a, and a distance between the extension part and the main plate is b, a value a/b is set according to a predetermined ratio.

8. The turbo fan according to claim 7, wherein when a length of the extension part is c, a value of a/c is set according to a predetermined ratio.

9. The turbo fan according to claim 7, further comprising an exhaust part disposed between the plurality of blades to provide a moving path of the air,

wherein the exhaust part comprises:

a first exhaust part disposed at an upper side of the extension part; and

a second exhaust part communicating with the first exhaust part, the second exhaust part disposed at a lower side of the extension part.

10. The turbo fan according to claim 9, wherein at least one of the first and second exhaust parts is defined as a space in which the outer circumferential part and the extension part are disposed.

11. The turbo fan according to claim 3, wherein the valley part has a length greater than a length of a surface at which the blade meets the shroud.

12. The turbo fan according to claim 3, wherein the valley part has a curvature radius greater than a curvature radius of a surface at which the blade meets the shroud.

13. A ceiling type air conditioner comprising:

a case defining an outer appearance, the case having a suction hole;

a fan motor disposed within the case;

a turbo fan disposed within the case to change a moving direction of air passing through the suction hole; and

a heat exchanger disposed outside the turbo fan,

wherein the turbo fan comprising:

a main plate rotated by power provided from the fan motor;

a plurality of blades, each blade having one end connected to the main plate to perform rotation movement; and

a shroud having an inner circumferential part and an outer circumferential part, an other end of each of the blades connected to the shroud,

wherein the shroud comprises:

a plurality of curved parts, each curved part having one side connected to the inner circumferential part and an other side connected to the outer circumferential part, the plurality of curved parts each having a predetermined curvature.

14. The ceiling type air conditioner according to claim 13, wherein at least one of the plurality of curved parts comprises a mountain part spaced away from the main plate.

15. The ceiling type air conditioner according to claim 14, wherein the plurality of curved parts comprise a first curved part and a second curved part disposed adjacent to the first curved part,

a valley part disposed on a boundary surface between the first curved part and the second curved part, the valley part being disposed spaced closer to the main plate than the mountain part; and

an inclined part connecting the mountain part to the valley part, the inclined part having the predetermined curvature.

16. The ceiling type air conditioner according to claim 13, wherein a first contact is a point at which the outer circumferential part and a blade meet, and a second contact is a point at which the outer circumferential part and an adjacent blade meet, the extension part defined as a virtual line connecting the first contact point and the second contact point. and a protrusion is a point at the outer circumferential part disposed spaced furthest away from the main plate,

wherein when a distance between the protrusion and the extension part is a, and a distance between the extension part and the main plate is b, a value a/b is set according to a predetermined ratio.

17. The ceiling type air conditioner according to claim 16, further comprising an exhaust part disposed between the plurality of blades to provide a moving path of the air,

wherein the exhaust part comprises:

a first exhaust part disposed at an upper side of the extension part; and

a second exhaust part communicating with the first exhaust part, the second exhaust part disposed at a lower side of the extension part.

18. The ceiling type air conditioner according to claim 14, further comprising:

a rotation shaft providing a rotation center of the main plate, and

a central line that is a virtual line defined when the rotation shaft and the virtual line extending through mountain part extend in parallel, wherein a distance between the mountain part and the inner circumferential part is greater than a distance between the mountain part and the outer circumferential part with respect to the central line.