JPH07127961A - Freezer/refrigerator - Google Patents

Abstract

PURPOSE:To provide a freezing refrigerator which includes a cold air circulation fan effective for low noise and low vibration, and which is excellent in fundamental performance such as cooling power, power saving, uniformization of temperature in a storage chamber, and prevention of frosting in a freezing chamber, and further which has a greater effective internal volume. CONSTITUTION:There is provided a reverse feed duct 20 extending branched from a spiral casing 9b for guiding part of cold air in a direction R different from a blowoff direction where a cold air flow is restricted by the spiral casing 9b. The reverse feed duct is constructed as a ventilation structure which is located upward of a shaft core of a fan on the spiral casing 9b and which is located on the side of the center of the spiral from a final end 9a of the spiral, and which has a blade recessed into an arc shape in its cross section and inclined backwardly in its mounting angle, and in which radial blade centrifugal fans 8 having a suction inlet 9c directed forwardly on the internal back surface of a box are vertically parallely disposed within the deapth of a cooler 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator / freezer, and more particularly to a refrigerator / freezer having a ventilation structure that is effective in reducing noise, reducing vibration, uniforming the temperature in a storage room, and preventing frost formation in the freezing room. is there.

[0002]

2. Description of the Related Art Generally, in a conventional refrigerator-freezer,
The cool air delivery duct from the cooler room accommodating the cooler to each storage room is meandering and has a large air path resistance.
Under such conditions where the air passage resistance is large, a centrifugal fan such as a high static pressure type sirocco fan has a smaller specific noise than a propeller fan, and it is easy to realize a low noise. But,
When a centrifugal fan is used, it plays the role of a cold air guide for giving directionality to the air discharged from the centrifugal fan on the circumference, and the gap in the outer peripheral direction of the centrifugal fan increases toward the air discharge side. A spiral case with a spiral shape
Thing is required.

A centrifugal fan, a cooler arranged below the suction side of the centrifugal fan, and a spiral case provided around the fan.
As a conventional refrigerating refrigerator having a structure in which a sing, a cold air delivery duct and an outlet grill communicating with the discharge side of the casing are provided to send cold air to the storage chamber, for example, the one described in JP-A-4-9565 is disclosed. Are known. FIG. 7 is a sectional view of a main part of the conventional refrigerator-freezer described in the above publication,
FIG. 8 is a perspective exploded view of essential parts of the refrigerator-freezer of FIG. 7.

In FIG. 7, 1 is an outer box of a refrigerator-freezer, 2
Is a heat insulating layer, 3 is a freezer, 6 is a cooler, and 7A is a cooler 6
, 8 is a centrifugal fan, 9A is a spiral casing plate corresponding to the first partition wall, 9B is a spiral casing, 10 is a fan motor, 12 is a support,
Reference numeral 14 is a partition plate corresponding to the second partition wall, 15 is a blowing grill, and 21A is a delivery duct for sending cold air.

In the refrigerator-freezer shown in FIG. 7, the centrifugal fan 8 and the spiral casing 9B are arranged in front of the position of the cooler 6,
In addition, it is arranged above the delivery duct 21A for sending cool air to the storage chamber, and the air outlet side having a large circumferential gap between the centrifugal fan 8 and the spiral casing 9B is located below the central axis of rotation of the centrifugal fan. The centrifugal fan 8 and the spiral casing 9B are efficiently housed by arranging the centrifugal fan 8 and the spiral casing 9B.

However, in such a structure, it is considered that the spiral casing 9B is a cold air guide for directing the air discharged from the centrifugal fan 8 on the circumference,
There is a problem that cold air can be easily distributed in a direction corresponding to the downstream of the end of the spiral of the spiral casing 9B, but cold air cannot be distributed in a direction corresponding to the center of the spiral from the end of the spiral.

[0007]

As described above, in the conventional example using the centrifugal fan and the spiral casing, the wind discharged from the centrifugal fan is regulated by the spiral casing and has a directivity. Therefore, although it is possible to install a cool air blowing grill in the blowing direction defined by the spiral casing, which is downstream from the end of the spiral of the spiral casing, the spiral casing corresponding to the center side of the spiral from the end of the spiral can be installed. There is a problem that it is difficult to guide the cool air in the direction opposite to the blowing direction defined by the sing and it is impossible to install the cold air blowing grill.

Further, since the position where the cold air blowing grill can be installed in the freezer compartment is affected by the spiral casing, it is impossible to evenly discharge the cold air and it is difficult to make the temperature distribution and the cooling rate uniform. . Furthermore, since it is difficult to evenly discharge cold air, when the door is opened and closed and when defrosting, the partition plate that separates the freezing room equipped with the cold air blowing grill and the freezing room partitioning parts are condensed and recooled, and the icicles are cooled. However, there is a problem in that it cannot prevent the frost from growing.

Next, a conventional centrifugal fan will be described. The centrifugal fan has various blade shapes, and the characteristics thereof are significantly different. Therefore, the selection of the blade shape is an important issue. For example, in a sirocco fan (also called a forward blade fan or a multi-blade fan), the absolute flow velocity (dynamic pressure) of discharge becomes large because the blade gap is narrowed on the fan outlet side. Further, the static pressure recovery action in the spiral casing is low, and the wind pressure (total pressure) required for the fan is high.

Furthermore, since the resistance in the duct portion which winds up and winds up increases, in order to obtain the same air volume as the propeller fan that has been generally used in the past, the noise is higher than that of the propeller fan, and the fan becomes large. If the speed is reduced, the output and torque of the fan motor are required to be large, and the size of the motor becomes large. Therefore, there is a problem in that a low-speed, high-torque fan motor is difficult to design in addition to the problems of the storage portion, increased vibration, increased input, and the like. Further, in order to increase the static pressure, there is a problem that the scroll size of the spiral casing becomes large and the storability is deteriorated.

Therefore, when the device is used while avoiding the problem of increasing the size, the air volume becomes insufficient, resulting in problems such as a reduction in refrigerating capacity and an increase in size of the compressor. Further, when the distribution duct is made large in order to reduce the ventilation resistance, there is a problem that the effective internal volume is affected and decreases.

On the other hand, in a centrifugal fan having a backward blade whose cross section is swollen in the rotational direction, the relative velocity between the blade and the flow must be increased because the insufficient air volume must be obtained by increasing the rotational speed or the impeller diameter. There was a problem that it became louder and the noise became louder. Increasing the size of parts directly affects the reduction of the effective internal volume of the storage room, and increasing the required pressure of the fan increases fan noise and pulsating vibration in the air duct, making it possible to reduce the flat surface of the refrigerator. Since many large boxes generate vibration noise with slight vibration, it has been desired to provide a ventilation structure for a refrigerator / freezer that solves these problems.

The present invention has been made in order to solve the above-mentioned problems of the prior art. The first object of the present invention is to enable uniform cold air discharge to a freezing chamber, and to improve temperature distribution and cooling rate. Not only does it become uniform, but even when the partition plate that separates the freezing room equipped with the cool air blowing grill and the freezing room partitioning parts condense when the door is opened and closed and when defrosting Another object of the present invention is to provide a freezer-refrigerator that can be dried to prevent it from growing into frost such as icicles.

A second object of the present invention is to provide a product having low noise and low vibration, excellent cooling power, low power consumption and a large effective internal volume. is there.

[0015]

In order to achieve the above-mentioned first object, the structure of a refrigerator-freezer according to the present invention has a centrifugal fan arranged on the back of the inside of the refrigerator and a cooling arranged below the suction side of the centrifugal fan. A refrigerator and a refrigerator provided with a container, a swirl casing provided around the fan, and a cool air distribution duct and an outlet grill communicating with the discharge side of the casing to send cool air to a storage chamber. -A back-feed duct extending separately from the spiral casing is provided for guiding a part of the cool air in a direction different from the blowing direction in which the flow of the cool air is regulated by the sing, and the back-feed duct is the spiral casing. The ventilation structure is located above the axial center of the upper fan and at a position closer to the center of the spiral than the end of the spiral.

More specifically, the reverse duct extending separately from the spiral casing has a guide guide rib, and the end face of the guide guide rib is located on the downstream side of the cold air circulation.
The cooling air is projected to the inside of the thing to guide the cooling air to the cooling air guide passage. That is, a notch is provided above the fan shaft center on the spiral casing and at a position closer to the center of the spiral than the end of the spiral, and a reverse feed duct and a blow-out grill extending from the notch are constituted to form the spiral casing. The cold air is discharged in a direction different from the regulated blowing direction.

Further, in order to achieve the above second object,
The configuration of the centrifugal fan of the refrigerator / freezer according to the present invention is such that the blade cross-sectional shape is dented on the side opposite to the rotational direction, the mounting angle of the blade is also inclined rearward on the side opposite to the rotational direction, and the blade outer peripheral surface is substantially radial. It is a radial wing.

More specifically, the outlet angle β ₂ at the outer peripheral end of the blade of the centrifugal fan is in the range of 70 ° to 105 °, and the inter-blade flow passage width gradually increases from the inlet side width a toward the outlet side width b. It becomes wider and the inner peripheral edge of the blade is located at least in the rotational direction rather than the radial direction. Further, it is characterized in that the blades of the centrifugal fan gradually decrease in inclination from the inner peripheral side toward the outer peripheral side.

[0019]

The function of each of the above technical means is as follows. By forming a notch above the axial center of the centrifugal fan on the spiral casing and at a position closer to the center of the spiral than the end of the spiral, and forming a reverse feed duct and an outlet grill extending from the notch, the spiral is formed. The cold air can be distributed in a direction different from the direction in which the cool air is blown by the casing, and the cold air can be evenly discharged into the freezer compartment to facilitate uniform temperature distribution and cooling rate. .

Further, since it becomes possible to uniformly discharge cold air,
Even when the partition plate that separates the freezing room equipped with the cool air blowing grill and the freezing room partitioning parts condense when the door is opened and closed and when defrosting, the dew is dried by the uniform cold air discharge, and icicles, etc. It is possible to prevent the growth of frost.

Next, the operation of the fan will be described. The cross-sectional shape of the blade is dented on the side opposite to the rotation direction, and the blade is attached
Flow is performed along the inlet side inclination of the blades, and between the blades, the flow velocity is gradually reduced toward the discharge side to increase the static pressure, and the absolute velocity direction flows along the rotation direction toward the discharge end of the blades. I am trying to make you. That is, the pressure loss between the blades is reduced by increasing the static pressure between the blades, not after the discharge. Further, not only does the pressure loss due to the spiral casing after discharge be reduced, but this also improves the velocity distribution of the discharge flow from the spiral casing, thus facilitating the reduction of losses in the distribution duct of the cool air, the blowing grill, etc. To do. Further, in the multi-blade configuration of the blade, the rotational first-order frequency can be moved to a significantly higher side, and the center of gravity can be moved inward due to the inclination of the blade cross section, so that resonance and resonance can be reduced.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 is a cross-sectional view of a main part of a refrigerator-freezer according to an embodiment of the present invention, FIG. 2 is a vertical cross-sectional view taken along the line AA of FIG. 1, and FIG. 4 is a partially enlarged view showing another example of the reverse feeding duct section, and FIG. 5 is an explanatory view showing a partially enlarged view and structural specifications of the radial blade centrifugal fan shown in FIG.

In FIGS. 1 and 2, 1 is an outer box of a refrigerator-freezer, 2 is a heat insulating layer, 3 is a freezer compartment related to a storage room, 4 is a refrigerating room related to the storage room, 5 is a refrigerating room 3 and a refrigerating room. A heat insulating wall for partitioning the chamber 4, 6 is a cooler installed on the back of the freezing chamber, 7
Is a cooling chamber that houses the cooler 6, and 8 is a radial blade centrifugal fan (hereinafter simply referred to as a centrifugal fan). Reference numeral 9 denotes a spiral casing plate arranged on the front surface of the centrifugal fan 8,
9b is a spiral casing. The spiral casing plate 9 extends to the rear side in the same direction as the axial center of the centrifugal fan 8,
The spiral casing 9b is formed by a rib in which the distance from the fan is gradually increased in a spiral shape in accordance with the rotation direction of the fan so that the almost end 9a of the spiral portion is brought close to the uppermost stage of the freezer compartment.
Is to have.

The spiral casing 9b spreads horizontally from substantially the end 9a of the spiral portion, and then extends downward to the side of the cooler 6 while drawing a gentle curve, and opens to the refrigerating chamber 4. A suction port 9c is located on the front side of the spiral casing plate 9 and is concentric with the centrifugal fan 8 and opens forward. Below the suction port 9c, the cold air cooled by the cooler 6 installed on the back side of the spiral casing plate 9 is cooled by the spiral casing plate 9.
Has a guide port 9d for guiding it to the front side, and is surrounded by a rib 9e extending to the front side in the same direction as the axial center of the centrifugal fan 8 together with the suction port 9c.

Reference numeral 10 denotes a fan motor which is directly connected to the centrifugal fan 8 and is supported by a back plate 11 of a spiral casing 9b and a support 12 via a vibration-proof rubber 13 and fastened to a box. . Reference numeral 14 is a partition plate that divides the freezing chamber 3 and the cooling chamber 7, and is provided with blowing grilles 15 and 20a. A pressure chamber 16 is formed by the inner surface side of the spiral casing 9b and the back plate 11, and a portion surrounded by the inner surface side of the rib 9e of the spiral casing plate 9 and the partition plate 14 and the outer surface side of the rib 9b are cooled. The negative pressure chamber 17 is formed by the portion surrounded by the chamber back wall (not shown).

The pressure chamber 16 is partially opened on the spiral casing plate 9 which does not interfere with the negative pressure chamber 17, and guides the cool air from the back side to the front side of the spiral casing plate 9. The cold air is discharged from the blowing grille 15 to the freezer compartment 3 via the cold air delivery duct 21 in the space between the partition plate 14 and the spiral casing plate 9. 18, 1
Reference numeral 9 denotes a return duct, which has one end open to the freezing compartment 3 and the refrigerating compartment 4 in the partition wall 5 and the other end communicating with the lower side of the cooler 6 and arranged substantially horizontally.

In the above structure, as shown in FIGS.
Above the axis of the centrifugal fan 8 on the spiral casing 9b,
In addition, a notch 9g is provided at a position closer to the center of the spiral than the end 9a of the spiral, and the reverse feeding duct 20 extends from the notch 9g.
Also, by constructing the blowing grille 20a, it is possible to distribute the cool air in a direction R different from the blowing direction Q of the cool air directed by the spiral casing 9b.

Further, as shown in FIG. 4, among the ribs of the reverse feeding duct 20, a guide guide rib 20b, which is the end face on the downstream side of the cold air circulation, is projected into the spiral casing 9b, whereby the spiral casing is formed. It is possible to efficiently discharge the cool air in the direction R different from the blowing direction Q of the cool air directed by 9b.

In the freezer-refrigerator constructed as described above, when the centrifugal fan 8 is rotated, the cold air that has been heat-exchanged in the cooler 6 and becomes low temperature passes through the guide port 9d and the centrifugal fan 8 from the suction port 9c. Is discharged to the outer peripheral direction by the guide, is guided to the spiral casing 9b, and is discharged to the freezing compartment 3 and the refrigerating compartment 4. The return from the freezer compartment 3 and the refrigerating compartment 4 passes through the return ducts 18 and 19 and enters the cooling compartment 7 from below the cooler 6. That is, the circulation of cold air in the refrigerator / freezer is always performed through the pressure chamber 16, the blowing grill 15, the return ducts 18 and 19, and the like.

By the way, if the delivery duct, the grill, etc. are made compact in order to increase the storage amount of food,
Since the ventilation resistance is increased and a fan with static pressure commensurate with the ventilation resistance is required, it can be said that the noise of the fan is increased. Here, the ventilation resistance is proportional to the square of the wind speed. If the cross section of the ventilation passage is reduced by 20% in area, the ventilation resistance will be 1.4 times, and the noise will be proportional to the square of the pressure, so it will be 20 × log (1 + 0.4) = 2.9 (dB) higher. Will be lost. The above-mentioned increase in noise can be said even when the absolute velocity of the discharge from the fan becomes large, or the wind velocity distribution is poor and the velocity is partially high.

Therefore, the radial blade centrifugal fan (centrifugal fan) 8 in this embodiment adopts a unique blade shape to solve the above problem. This will be described below with reference to FIG. As shown in FIG. 5, the centrifugal fan 8 according to the present embodiment has a blade 8a whose cross-sectional shape is dented in an arc shape opposite to the rotation direction N indicated by the arrow, and the whole is tilted backward to the side opposite to the rotation direction N. ,
The radial blade centrifugal fan has a radial blade outlet end 8aa in a substantially radial direction. Therefore, as for the width of the flow path between the blades, the dimension b on the outlet side is larger than the dimension a on the inlet side. Therefore, the air flow between the blades becomes a deceleration flow, and the dynamic pressure is converted into static pressure by the time it comes out from between the blades. Will increase the dynamic pressure).

Therefore, static pressure recovery in the spiral casing 9b around the centrifugal fan 8 is not required so much, and the spiral casing 9b can be made compact. Further, the flow velocity distribution sent out from the spiral casing 9b also becomes good for the same reason, and the pressure chamber 16 is predominantly made to have a static pressure, and the blowing grill 15 has a small ventilation resistance.
To the freezer compartment 3 and from the lower outlet 9f to the refrigerating compartment 4 easily. Therefore, since the ventilation resistance is small, the pressure of the fan can be lowered.

As shown in FIG. 5, since the relative velocity W ₂ between the blade 8a and the flow is small at the blade discharge end 8aa, not only the noise is reduced, but also the blade gradually follows the rotation direction as it goes to the blade discharge end 8aa. Since the absolute velocity C ₂ is created, the collision with the spiral casing becomes small and the loss is reduced. Meanwhile, wings 8
At the blade inlet end 8ab in the radial direction of a, the inflow relative velocity W ₁
Since it is designed to continuously approach the direction of rotation from the indented side along the direction of, the occurrence of turbulence when flowing into the blade is small and low noise can be obtained.

Further, since the static pressure of the centrifugal fan is obtained by increasing the rotation speed to some extent, the required torque is small due to the high rotation speed to obtain the same output, and a normal small 2-pole induction motor can be used. Therefore, it can be used at a high efficiency speed point, and the input of the fan motor 10 can be lowered,
Cooling capacity can be improved as well as power saving. Further, since there is a large static pressure between the blades, the spiral casing 9 and the pressure chamber 1
Since deceleration (expansion flow) in 6 and the like can be reduced, vortex generation is reduced, pulsation flow is reduced, and resonance and resonance in the ventilation passage can be reduced. In addition, the inclination of the blade cross section becomes smaller as it goes outward in the radial direction, so that the center of gravity of the blade is in the center direction, the starting torque of the fan motor can be made small, and the vibration can be reduced.

Furthermore, since the number of blades is a multi-blade type, which is several times (5 to 10 times) larger than that of the conventional propeller fan, the rotation frequency of the blades is several times higher, and the natural frequency of the refrigerator-freezer box ( Generally, it can be moved away from 100 to 300 Hz (150 to 200 Hz for a 4-blade propeller fan, and 5 times 75 because the centrifugal fan of the present invention has 20 or more blades).
0 Hz or higher), and resonance or resonance is reduced even if vibration is applied via the fan motor 10 or air flow path is excited by fluid. Further, since the main frequency of noise is high due to the high rotation frequency of the blades, the sound insulation effect of the box body is large, but the radiated noise emitted to the outside is also low.

Next, advantages of the arrangement structure of the centrifugal fan 8 of this embodiment will be described. The centrifugal fan 8 and the spiral casing 9b around the centrifugal fan 8 are located on the back surface inside the box body, open the suction port 9c toward the front, and the pressure chamber 16 is on the side in communication with the spiral casing 9b. Since the centrifugal fan with radial blades is used as the fan, the static pressure is advanced before the wind enters the spiral casing 9b, and the spiral casing 9b can be made into a small scroll. For this reason, since the size of the casing in the vertical direction can be made small, it can be easily juxtaposed vertically within the thickness dimension of the front and rear of the cooler 6 arranged on the back surface inside the box body, and the effective internal volume in which food can be stored is large. You are getting the effect.

According to the experiment, in the centrifugal fan 8 of this embodiment, as compared with the case of using the sirocco fan having the same diameter,
It has been confirmed that the height of the discharge port (the end 9a portion) can be reduced by 15 to 20%. Further, with the above structure, the fan motor 10 can be housed on the side of the heat insulating layer 2 not related to the ventilation passage, and the length of the shaft can be shortened.

Further, in the centrifugal fan 8 of the present embodiment, the amount of air flow can be increased, the vibration of the fan motor 10 can be reduced, and the fan motor 10 can be supported by the back plate 11 of the spiral casing 9b. Further, it is possible to easily support a shaft center with little vibration without requiring any new parts, and the fan motor 10 is sealed in the recessed portion 2a of the heat insulating layer 2 by the back plate 11 so that the fan motor 10 is not exposed to the dew. The effect of preventing sticking and radiating a part of the heat generated from the fan motor 10 to the outside of the box from the rear side and improving the cooling capacity inside the box can be obtained.

Next, in order to confirm that the radial blade centrifugal fan (centrifugal fan 8) is good, actually measured data will be described in detail with reference to FIG. FIG. 6 is a diagram showing the performance of the radial blade centrifugal fan of the present invention in comparison with other types of fans. The horizontal axis in FIG. 6 is the exit angle β ₂ ,
The vertical axis represents the noise level SL, the required rotation speed Nf, the required torque T, and the total pressure efficiency η.

In the experiment, the outer shape D ₂ shown in FIG.
Inner diameter D ₁ is 68 mm, axial thickness is 30 mm, number of blades is 30
When using the centrifugal fan of No.1 to obtain a constant total pressure (20Pa) at an air flow rate of 0.85m ³ / min under the same ventilation resistance load conditions as a refrigerator / refrigerator with an effective internal volume of 370l (liters). , The performance of the fan alone was measured by changing the blade cross-sectional shape variously, the noise level at the position 1 m in front of the spiral casing discharge port was SL, and the required rotation speed at that time was Nf, in relation to the outlet angle β ₂ of the blade. The required torque T and total pressure efficiency η are arranged.

In the figure, the alternate long and short dash line indicates the case of a so-called backward blade centrifugal fan in which the blade cross-sectional shape has a bulge with respect to the rotation direction and the whole is tilted backward in the opposite direction with respect to the rotation direction, and the broken line is The case of a so-called forward blade centrifugal fan in which the blade cross-sectional shape is dented in the rotational direction and the whole is inclined forward in the rotational direction is shown. The solid line is dented in the rotational direction in the present invention, and the whole is opposite to the rotational direction. It shows the case of a radial blade centrifugal fan that tilts backward.

As is apparent from FIG. 6, the radial blade centrifugal fan has an outlet angle β _{2 in the} range of 70 ° to 105 °.
The noise SL is clearly lower than that of the forward blade centrifugal fan. The reason for this is that, as described above, the relative velocity W ₂ of the flow with respect to the blades is the lowest, so that there is little turbulence between the blades and at the blade outlet end 8aa, and the blade inlet end 8ab is along the wind inflow direction. This is because the static pressure recovery in the spiral casing is also performed gently. Therefore, the fan efficiency η is high, and the required rotation speed Nf is high.
Is more than 2000 revolutions per minute, and can be sufficiently operated by a normal small 2-pole fan motor.

Further, the noise is higher in the forward blade centrifugal fan in which the entire blade is inclined in the rotation direction than in the radial blade centrifugal fan. The reason for this is that the outlet-side inter-blade air passage width dimension becomes small due to the inclination of the blades, and the relative speed W ₂ with the blades becomes large as the absolute velocity C ₂ that passes increases, so that the inter-blade and blade outlet ends are increased. This is because the turbulence increases and the absolute velocity of the dynamic pressure is large, so that the turbulence due to the enlarged passage of the spiral casing and the loss inside the casing due to the high-speed portion increase. For this reason, the fan efficiency η is also reduced, and the required rotation speed Nf is also lower than 2000 rotations per minute, which is a point where the slip ratio is too large in a normal small 2-pole induction motor, that is, the rotation speed is low. As a result, the torque value is used in a region where the torque value decreases, and the rotational speed fluctuates due to a slight fluctuation of the power supply voltage or a fluctuation of the fan load, which causes a problem that the two-pole induction motor cannot be practically used.

Further, in order to carry out the same work at a low rotation speed, a low rotation speed and a large required torque are required, and together with a large slip ratio of the rotation speed,
There is a problem that the efficiency of the fan motor decreases and the input increases. On the other hand, it is conceivable to reduce the outer diameter of the fan in order to increase the rotation speed, but the air volume decreases in proportion to the third power of the outer diameter, which causes a problem of insufficient air volume.

On the other hand, the noise SL is high in the backward blade centrifugal fan. The reason for this is that the relative speed becomes large and the wind pressure becomes low because the rotational speed Nf is increased to cover the peripheral speed by increasing it. Therefore, the loss in the blade is large and the efficiency is reduced. In order to improve this, it becomes necessary to make it larger, and new problems arise such as storability, increase in material cost, and increase in vibration.

The hatched data points in FIG. 6 were actually installed in the refrigerator / freezer, and only the fan was operated to set the rotation speed at which the air flow rate was 0.85 m ³ / min (therefore ignoring the fan unit test). Then, the β ₂ = 90 ° radial blade centrifugal fan was installed with a microphone at a distance (0.35 m in front of the box) that produces the same noise as the fan unit test, and a forward blade centrifugal fan and backward blade centrifugal fan are installed. This is an example of measuring the noise of a shaped fan. With the forward-blade centrifugal fan, the rotation speed was increased by 9% and the same air volume was obtained, and the noise was increased by 3 dB compared with the time when the fan alone was evaluated.

This is because the static pressure recovery is not good, so the pressure chamber 16 and the blow-out grill 1 at the high-velocity flow portion.
5, and the ventilation resistance of the lower outlet 9c and the like is increased. In the backward blade centrifugal fan, the noise increased by 1 dB. This was due to the high motor vibration due to the high rotation speed.

As described above, the actual measurement performance of the blade shape based on the data is explained, and the shape of the blade has a great influence on the performance. By using the radial blade centrifugal fan of the present invention, low noise can be achieved. It was confirmed that the fan motor used in combination with this was also a small two-pole induction motor and could operate efficiently. It was also confirmed that when applied to a refrigerator / freezer that requires a delivery duct, a grill, etc., the effect is greater than the noise level difference between fans alone.

Next, the main specifications associated with the blade shape of the radial blade centrifugal fan of the present invention will be explained.
₁ 0.7D ₂ ~0.88D ₂ (the outer diameter and D _2), the wing number Z is 0.25D ₂ ~0.5D _2, the indentations curvature radius R of the blade 0.085D ₂ ~0.16D ₂ and the blade exit angle β ₂ is 7
It is preferable to have a shape in which the installation angle θ (inclination) of the entire blade is 0 ° to 105 °, and is inclined rearward in the direction opposite to the rotation direction.

[0050]

As described in detail above, according to the present invention, a notch is provided above the axis of the fan on the spiral casing and at a position closer to the center of the spiral than the end of the spiral. By constructing a cool air guide passage extending from the notch and a blowout grill, and installing a reverse duct for discharging cool air in a direction different from the blowout direction in which the cool air is regulated by the spiral casing and directed, With this structure, it is possible to evenly discharge cold air to the freezer, which was difficult with the above structure, and not only the temperature distribution and cooling rate become uniform, but also when the door is opened and closed and when defrosting, the freezer with a cool air blowing grill and cooling It is possible to provide a freezer-refrigerator that can prevent dew from being dried by even discharge of cool air and growing into frost such as icicles even if a partition plate for partitioning the chamber and a freezing compartment partitioning component condense.

Further, according to the present invention, the shape of the blade is dented in an arc shape on the side opposite to the rotating direction, the mounting angle of the blade is inclined rearward opposite to the rotating direction, and the blade outer peripheral end is directed substantially in the radial direction. A radial-blade centrifugal fan structure with a peripheral edge closer to the rotation direction is used, and in a refrigerator / freezer that uses a distribution duct, a blow-out grill, etc., it is placed side-by-side with the cooler on the back of the inside within the depth dimension of the cooler. Since it is used, a product with low noise and low vibration can be provided, and further, a refrigerator-freezer with excellent cooling power, low power consumption, and large effective internal volume can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of essential parts of a refrigerator-freezer according to an embodiment of the present invention.

FIG. 2 is a vertical sectional view taken along the line AA of FIG.

FIG. 3 is a partially enlarged view of a reverse feeding duct portion.

FIG. 4 is a partially enlarged view showing another example of the reverse feeding duct section.

5A and 5B are explanatory views showing a partial enlargement and a structural specification of the radial blade centrifugal fan of FIG.

FIG. 6 is a diagram showing the performance of the radial blade centrifugal fan of the present invention in comparison with other types of fans.

FIG. 7 is a cross-sectional view of essential parts of a conventional refrigerator-freezer.

8 is a perspective exploded view of a main part of the refrigerator-freezer of FIG. 7. FIG.

[Explanation of symbols]

3 ... Freezing room, 4 ... Refrigerating room, 6 ... Cooler, 7 ... Cooling room, 8
... Centrifugal fan, 8a ... Blades, 9 ... Vortex casing press
9a ... end, 9b ... spiral casing, 9c ... suction opening, 9d ... guide opening, 9e ... rib, 10 ... fan motor,
Reference numeral 14 ... Partition plate, 15 ... Blow-out grill, 20 ... Back-feed duct, 20a ... Blow-out grill, 20b ... Guide guide ribs, 21 ... Cold air delivery duct.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location G10K 11/16 (72) Inventor Seiichi Abe 800 Tomita, Ohira-cho, Shimotsuga-gun, Tochigi Hitachi, Ltd. Living Equipment Division Cooling & Heat Headquarters (72) Inventor Yutaka Shimoda 800 Tomita, Ohira Town, Shimotsuga-gun, Tochigi Prefecture Hitachi Ltd. Living Equipment Division Cooling & Heat Headquarters (72) Inventor Nomura First 800, Tomita, Hitachi, Ltd., Heating and Cooling Division, Living Equipment Division (72) Inventor Takashi Tsuchiya 800, Oita, Shimotsuga-gun, Tochigi Prefecture Tomita 800, Living Equipment Division, Hitachi, Ltd.

Claims (5)

[Claims] 1. A centrifugal fan arranged on the back side of the inside of the refrigerator, a cooler arranged on the lower side of the suction side of the centrifugal fan, a spiral casing provided around the fan, and cold air communicating with the discharge side of the casing. In a freezer-refrigerator equipped with a delivery duct and a blowing grill for sending cold air to a storage room, a part of the cold air is guided in a direction different from the blowing direction in which the flow of the cool air is regulated by the spiral casing. A reverse feeding duct that extends separately from the spiral casing is provided.
A refrigerator-freezer characterized in that the back-feed duct has a ventilation structure which is located above the axis of the fan on the spiral casing and at a position closer to the center of the spiral than the end of the spiral. 2. A back-feed duct extending separately from the spiral casing has a guide guide rib, and an end face of the guide guide rib is projected into the spiral casing which is on the downstream side of the cold air circulation, and into a cold air guide passage. The refrigerator-freezer according to claim 1, wherein the cold air is induced. 3. A centrifugal fan whose radial cross section is indented on the side opposite to the rotational direction, whose mounting angle is also inclined rearward on the side opposite to the rotational direction, and whose outer peripheral surface is substantially radial. The refrigerator / freezer according to claim 1, wherein 4. The outlet angle β ₂ at the outer peripheral end of the blade of the centrifugal fan is in the range of 70 ° to 105 °, and the width of the inter-blade passage gradually becomes wider toward the outlet side width b than the inlet side width a. The refrigerator according to claim 3, wherein the inner peripheral end of the blade is located at least in the rotational direction from the radial direction. 5. The centrifugal fan blade inclination is gradually reduced from the inner peripheral side toward the outer peripheral side.
Alternatively, the refrigerator-freezer according to any one of 4 above.