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Top plate structure for high location installation type air conditioner

Top plate structure for high location installation type air conditioner description/claims

The present invention relates to a top plate structure for a high location installation type air conditioner.

An indoor unit for a high location installation type air conditioner, such as an air conditioner concealed in or suspended from a ceiling of a house, includes, for example, a metal top plate forming a top surface of a cassette body casing. The air conditioner is concealed in the ceiling or suspended from a lower surface of the ceiling by suspending heavy objects such as a heat exchanger, fan, and fan motor from the top plate and then suspending the main body casing with suspension bolts or the like.

FIGS. 22 to 24 show a ceiling concealed air conditioner as one example of a high location installation type air conditioner. As shown in FIGS. 22 to 24, the air conditioner includes an air conditioner body 1, which is arranged in an upper part of an opening 7 formed in a ceiling C, and a decorative panel 2, which is attached to the body 1 to cover the opening 7. The body 1 has a cassette body casing 3, in which a generally annular heat exchanger 4 is arranged. A fan (impeller) 5 and a fan motor 9 are arranged in a central portion of the heat exchanger 4 in the body casing 3 in such a manner that an air inlet side of the fan 5 faces downward and an air outlet side of the fan 5 faces the side of the heat exchanger 4. A bell mouth 6 made of synthetic resin is arranged at the air inlet side of the fan 5 in the body casing 3.

The fan 5 is formed by a centrifugal fan having a large number of blades 5b arranged between a hub 5b and a shroud 5c. A drain pan 8 is arranged below the heat exchanger 4. An air outlet passage 10 is formed around the periphery of the heat exchanger 4.

The body casing 3 is generally hexagonal and includes a side wall 31 and a top plate 32. The side wall 31 is formed from a heat insulating material. The top plate 32 covers an upper portion of the side wall 31. The heat exchanger 4 includes a pair of opposing open ends. A tube plate 11 is arranged on each open end of the heat exchanger 4. The tube plates 11 are connected to each other by a predetermined partition plate 12.

The top plate 32 of the body casing 3, the tube plates 11, the partition plate 12, and a switch box 13 attached to a lower surface of the bell mouth 6 are all formed from metal plates. As shown in FIG. 24, the top plate 32 and the switch box 13 are fixed to the top and bottom ends of the partition plate 12 by screws.

The bell mouth 6 has a recessed portion 14 for accommodating the switch box 13. An opening 16 is formed in a top surface 14a of the recessed portion 14. A switch box joint 15 formed on a lower end portion of the partition plate 12 is arranged in the opening 16. Two mounting pieces 17, which project integrally from two sides of an upper end portion of the partition plate 12, are connected to the top plate 32. The mounting pieces 17 are fixed to the top plate 32 from under the top plate 32 by screws 18.

Two mounting pieces 19, which project integrally from two sides of a lower end portion of the partition plate 12, are connected to the lower ends of the two tube plates 11. A mounting piece 15 connected to the switch box 13 is welded and fixed to an intermediate position of the partition plate 12. Each mounting piece 19 is fixed to the corresponding tube plate 11 from under the tube plate 11 by a screw 20. Each mounting piece 15 includes an L-shaped base portion 15a and a mounting portion 15b. The base portion 15a is connected to the partition plate 12. The mounting portion 15b extends downward from a distal end of the base portion 15a and is formed integrally with the base portion 15a. In a state in which the mounting portion 15b is arranged in the recessed portion 14 through the opening 16, each mounting piece 15 is fixed to a top surface 13a of the switch box 13 by screws 21.

The air conditioner includes a drain pump 22, a float switch 23, a drain pump accommodation portion 24 in which the drain pump 22 is arranged, a partition plate 25 partitioning the drain pump accommodation portion 24, and a lid 26 of the switch box 13.

The top plate 32 is hexagonal and shaped in correspondence with the body casing 3 of the air conditioner body 1. The top plate 32 has a peripheral portion along which a hook-shaped rim portion 32c is formed. The rim portion 32c is for fitting the top plate 32 and a peripheral portion at the upper end of the body casing 3 with each other.

The top plate 32 has a plurality of main reinforcing ribs 32a extending radially from a central portion 33 of the top plate 32 at which the fan 5 and the fan motor 9 are supported to a peripheral portion of the top plate 32 at which the generally annular heat exchanger 4 is supported. The main reinforcing ribs 32a are recessed in a downward direction. Each main reinforcing rib 32a has a predetermined width and a predetermined depth. Each main reinforcing rib 32a includes an outer part defining a heat exchanger support portion having a step portion 32b with a smaller recess depth. The main reinforcing ribs 32a enable the top plate 32 to have the required levels of basic rigidity, strength, deflection, and vibration characteristics.

The interval between the main reinforcing ribs 32a increases toward the peripheral portion of the top plate 32. This made result in the top plate 32 having insufficient rigidity and strength. Accordingly, a plurality of sub-reinforcing ribs 34 are arranged between the main reinforcing ribs 32a as shown in FIG. 24. The shape and dimensions of the sub-reinforcing ribs 34 are determined in accordance with the load that can be assumed to be applied to the top plate 32.

This structure is designed to reduce the static deflection of the top plate 32 to or below a fixed value and maintains the primary natural vibration frequency of the top plate 32 to or above a fixed value to avoid resonance caused by rotation of the fan motor 9.

The top plate 32 further includes a reinforcing rib 33a, which is triangular when viewed from above, arranged in at the central portion 33 where the fan 5 and the fan motor 9 are supported. This improves the rigidity, strength, deflection, and vibration characteristics of the supporting portion of the fan 5 and the fan motor 9 (refer to patent document 1).

The supporting portion of the fan 5 and the fan motor 9 includes a circular groove formed in each corner of the reinforcing rib 33a. The reinforcing rib 33a includes three fan motor mounting portions a, b, and c formed in central portions of the circular grooves. The fan motor 9 is suspended from and fixed to the fan motor mounting portions a, b, and c by mount members 11, which absorb vibrations, and a mounting bracket 9b. This rotatably supports the fan 5 by means of a motor shaft 9a.

Patent Document 1: Japanese Laid-Open Patent Publication No. 11-201496

In recent years, the cost of the air conditioner is required to be reduced from various perspectives. The cost of the top plate 32 used in the air conditioner is also required to be reduced. To reduce the cost of the top plate 32, the plate thickness of the entire the top plate 32 (for example, 0.8 mm) may be reduced (for example, to about 0.7 to 0.6 mm) to reduce material cost and facilitate formation of the ribs etc. However, reduction in the plate width would lower the rigidity and strength of the top plate 32 and require measures for suppressing vibrations of the top plate 32 generated when driving of the fan.

A top plate formed with a lower plate thickness than the existing plate decreases material cost and is easily deformed. This enables the force that is required for pressing and forming the top plate and facilitates formation of the top plate. However, when a thinner top plate includes the radial reinforcing ribs of the above-described conventional structure, the amount of static deflection increases and the primary natural vibration frequency resulting from rotation of the fan motor 9 decreases. As a result, the top plate would not satisfy the design standards.

Accordingly, it is an object of the present invention to provide a top plate structure for an air conditioner that enables a top plate that is thin yet has the required rigidity, strength, and vibration characteristics.

A first aspect of the present invention provides a top plate structure for an air conditioner including a body casing for accommodating a fan, a fan motor, and a heat exchanger. A top plate forming a top surface of the body casing suspends the fan, the fan motor, and the heat exchanger. The top plate has a plurality of radial reinforcing ribs extending from a central portion of the top plate at which the fan motor is supported to a peripheral portion of the top plate at which the heat exchanger is supported. The plurality of reinforcing ribs include a reinforcing rib protruding from a front surface of the top plate and a reinforcing rib protruding from a rear surface of the top plate.

• Provisional Patent
• Utility Patent

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