JPH0361473B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a clothes dryer, and in particular, a rotating drum, a heat source section, a blower fan for sending hot air from the heat source section to the rotating drum, The present invention relates to a so-called rotating drum type dryer equipped with this blower fan and an electric motor for rotationally driving the rotating drum, and the main body of the dryer is miniaturized, the structure is simplified, and the cost is reduced. This relates to clothes dryers.

[Prior art]

In general, many clothes dryers are of the so-called rotating drum type, which includes a cylindrical rotating drum inside a rectangular parallelepiped outer frame.

In this type of clothes dryer, the electric motor is arranged at a corner of the outer frame so that its rotational axis is parallel to the rotational axis of the rotating drum, and the blower fan is aligned with the rotational axis of the electric motor. If it is attached directly or to a drive pulley provided on the rotating shaft, the structure is simple and can be manufactured at low cost.

However, in the past, a four-pole, single-phase induction motor was used as the motor, so there was a limit depending on the rotation speed of the rotating drum, and the rotation speed of the motor was low to obtain the air volume necessary to satisfy the drying performance. However, the blower fan had to be made considerably large, which resulted in a large dryer body.

As a means to solve this problem, it is possible to use a speed increasing mechanism to increase the rotation speed of the fan and make the fan smaller. Possible measures include increasing the size of the fan and thereby reducing the size of the blower fan.

However, each of these means has the following drawbacks and is difficult to adopt immediately.

That is, first of all, the former method of increasing the rotation speed of the blower fan using a speed increasing mechanism requires a new speed increasing mechanism, so its structure is complicated;
It has the disadvantage of being expensive.

Next, the latter method described above has the disadvantage that the transmission mechanism for decelerating the rotation of the electric motor to the rotating drum is expensive for the reason described below. Describe.

In other words, in rotary drum type clothes dryers, the driving method for the rotary drum is generally a drive pulley attached to the rotating shaft of an electric motor and a drive pulley attached to the rotating shaft of the electric motor, due to advantages in terms of simple structure, noise, cost, etc. A method is used in which a belt is directly applied to the outer periphery of the rotary drum to drive the rotary drum at a reduced speed.

FIG. 1 is an explanatory diagram of the principle of this belt drive system.

In the figure, P is a rotating drum, Q is a belt, R is a drive pulley attached to the rotating shaft of the electric motor, and S
is a tension pulley that constantly presses the belt Q.

In such a configuration, the rotational speed N _D of the rotating drum P is determined by the outer diameter of the drive pulley R being d, the outer diameter of the rotating drum P being D, and the rotational speed of the electric motor being N _M
Then, N _D =d/D×N _M ...(1) is given.

In fact, instead of the value of d in equation (1),
The diameter d _P of the pitch circle should be used, but this diameter d _P varies depending on the type of belt even for drive pulleys with the same outer diameter, so for convenience, here,
Conditions where the outer diameter of the drive pulley R can be maximized,
That is, considering the case where d=d _P (assuming that the belt Q is extremely thin), the outer diameter of the drive pulley R is used as is.

Let us now consider the actual values of each of the above.

The outer diameter dimension D of the rotating drum P is approximately determined by the outer diameter dimension of the outer frame.

Generally, household clothes dryers are often installed above washing machines due to installation efficiency within the house.

Accordingly, the width of the outer frame is preferably equal to or smaller than the width of the washing machine in order to minimize the installation space.

In addition, there are two types of washing machines in general, fully automatic washing machines and two-tank washing machines, and in response to this, clothes dryers also have different height dimensions.
There is a vertical type with a smaller width (convenient when used in combination with a fully automatic washing machine), and a horizontal type with a larger width in the height direction (convenient when used in combination with a two-tub washing machine). There are two types of rotary drums (a good type), but the rotary drum P is usually used in common in terms of productivity.

Therefore, the outer diameter dimension D of the rotating drum P is almost determined by the width dimension of the vertically long type.

The width of most fully automatic washing machines is around 600mm.

Therefore, it is preferable that the width of the clothes dryer is approximately 600 mm.

Therefore, it is necessary to provide a gap between the rotating drum P and the outer frame.
Therefore, the outer diameter D of the rotating drum P is 580 mm (600-20 mm).
=580) or less.

In addition, the rotational speed N _M of an electric motor is generally expressed by its slip rate {slip rate = (synchronous rotational speed - actual load rotational speed) / (synchronous rotational speed) · 100%}, which is usually expressed as a few percent. For example, when the slip rate is 5%, at a power frequency of 60 Hz, in the case of a two-pole single-phase induction motor, the rotation rate is 3420 revolutions per minute.

On the other hand, the rotation speed N _D of the rotating drum P mentioned earlier
has limitations in terms of drying performance.

In other words, since the rotating drum P stores clothing therein and rotates and agitates the clothing, if the number of revolutions becomes too high, the centrifugal force of the rotation will cause the clothing to break against the inner circumferential wall of the rotating drum P. The rotational speed N _D of the rotating drum P must be set so that the centrifugal force exerted on the clothes is less than the gravitational force.

Therefore, for a rotating drum P with an outer diameter D of 580 mm, the acceleration of gravity > D/2 × (2πN _D /60) ²
......(2), the rotation speed N _D of the rotating drum P is <55.5 revolutions per minute. (The thickness of the outer peripheral wall of the rotating drum P is
Since it is very small compared to the outer diameter dimension D, this was ignored when handling it. ) Therefore, the outer diameter d of the drive pulley R is the rotation speed of the electric motor N _M = 3420 revolutions per minute, the rotation speed N _D of the rotating drum P = 55.5 revolutions per minute, and the outer diameter dimension D of the rotating drum P. = 580 mm, and according to equation (1) above, d < 55.5/3420 x 580 = 9.41 mm.

Moreover, the actual rotational speed N _D of the rotating drum P is
It is determined by the pitch circle diameter d _P mentioned earlier, and generally d _P
Since ≧d, the outer diameter dimension d of the drive pulley R
may need to be made even smaller depending on belt selection.

However, in cases where belt transmission requires transmission power of several tens of watts, such as in a clothes dryer,
If the outer diameter of the drive pulley is made smaller, the radius of curvature of the belt becomes smaller, which shortens the life of the belt and makes it more likely to slip. Accordingly, empirically, the outer diameter d of the drive pulley R should be at least
It is desirable to have a diameter of 10 mm or more, and it cannot be less than this. If it is less than that, slippage will easily occur, making it difficult to use the belt transmission itself. As a countermeasure for this, the above In order to deal with the shortening of the service life and the tendency to slip, a special belt is required, for example, a belt with a very thin thickness and a wide width, which is expensive.

As described above, when trying to use a two-pole single-phase induction motor as in the latter case, a special belt is required, which has the disadvantage of being expensive.
Moreover, it is difficult to use the belt transmission itself, and there are cases where other complex structures such as gear reduction and other expensive means have to be adopted, and these make it difficult to use the clothes dryer. A motor using a bipolar single-phase induction motor was difficult to develop and was never realized.

[Purpose of the invention]

The present invention eliminates the drawbacks of the prior art, solves the problems when using a two-pole single-phase induction motor, and makes it possible to make the outer diameter of the drive pulley equal to or larger than the minimum allowable diameter. The object of the present invention is to provide a rotary drum type clothes dryer which has a simple structure, is driven by an inexpensive belt using belt transmission, and can be downsized.

[Summary of the invention]

The clothes dryer according to the present invention has an outer frame, a rotating drum rotatably supported within the outer frame,
a heat source, a blower fan, an electric motor for driving the rotary drum and the blower fan, a drive pulley provided on the rotating shaft of the motor, and a drive pulley that is hung between the drive pulley and the outer periphery of the rotary drum. A belt for transmitting the rotational force of an electric motor to a rotating drum, in which the outer diameter of the rotating drum is 580 mm or less, the motor is a two-pole single-phase induction motor, and the power frequency is 60 Hz. When the motor has a rotation speed of 3,200 revolutions per minute or less, and when the motor has a rotation speed of 1,500 revolutions per minute or more when the motor is 50Hz, it is a high slip rate motor.

The details are as follows.

That is, in the present invention, the outer diameter of the rotating drum is
For items of 580 mm or less, use a two-pole, single-phase induction motor, and set the outer diameter of the drive pulley to 10 mm.
In order to achieve the above value, the actual load rotational speed is reduced as a two-pole, single-phase induction motor with a high slip ratio.

Now, the proper actual load rotation speed of the electric motor is expressed as follows using equation (1) mentioned earlier.

Rotation speed of the electric motor N _M = D/d x N _D In this formula, the minimum allowable diameter of the drive pulley d = 10 mm and the maximum allowable rotation speed of the rotating drum as mentioned earlier.
N _D = 55.5 revolutions per minute, maximum allowable diameter of rotating drum D
= 580 mm, the rotation speed of the electric motor will be approximately 3200 revolutions per minute or less, and approximately 3200 revolutions per minute will be the upper limit.

Also, the rotational speed of the motor does not need to be lower than that of a four-pole single-phase induction motor (because
In this case, a four-pole single-phase induction motor may be used. ), so it is more than 1500 revolutions per minute,
The lower limit is 1500 revolutions per minute.

Therefore, considering the frequency of the power supply used, when the frequency of the power supply is 60Hz, the number of revolutions is 3200.
A two-pole, single-phase induction motor with a high slip rate in the range where the rotation speed is less than 1,500 revolutions per minute when the power supply frequency is 50 Hz, which means that the slip ratio is approximately 11.1%. It is sufficient to use a two-pole, single-phase induction motor with a high slip ratio in the range of 50% to 50%.

[Embodiments of the invention]

An embodiment of the clothes dryer according to the present invention will be described with reference to FIGS. 2 to 4.

Here, FIG. 2 is a longitudinal cross-sectional view of a clothes dryer according to an embodiment of the present invention, and FIG.
FIG. 4, which is a sectional view taken along the line, is a relationship curve diagram showing the characteristics of the blower fan and the required air volume-pressure of the blower fan.

In Figures 2 and 3, 1 is an outer frame having a rectangular parallelepiped shape, 2 is a rotating drum, 3 is a heat source, 4, 5
are the rotating shafts 1 at the rear and front parts of the electric motor 6
A blower fan and a cooling fan are directly attached to the rotary drum 2, and the rotary shaft 14 is arranged parallel to the rotary shaft of the rotary drum 2.

The electric motor 6 is a two-pole, single-phase induction motor, and is set to have a high slip rate such that the slip rate under actual load is 20%.

That is, the electric motor 6 of this embodiment has a frequency of 60Hz.
2880 revolutions per minute, 2400 revolutions per minute at 50Hz.

Further, 7 is a belt that is directly applied to the drive pulley 15 attached to the rotating shaft 14 of the electric motor 6 and the outer periphery of the rotating drum 2 to transmit the rotation of the electric motor 6 to the rotating drum 2 at a reduced speed.

8 is a partition body for accommodating the electric motor 6 and the cooling fan 5 in isolation from the inside of the outer frame 1;
10 is a rotating drum support, 10 is a back cover, 11 is a circulation duct composed of the rotating drum support 9 and the back cover 10, 12 is a cooling air guide, 13 is a drain port, 16
is a tension pulley that constantly presses the belt 7 to prevent it from sagging.

In this embodiment, the blower fan 4 is connected to the electric motor 6.
The rotation shaft 14 of the electric motor 6 is directly connected to the rotating shaft 14 of the electric motor 6.
For example, by shortening the rotating shaft 14 without transmitting the information,
The blower fan 4 may be fixed to the drive pulley 15 so as to be rotated via the drive pulley 15.

In such a configuration, as shown by the solid line arrow in FIG. , is emitted into the outer frame 1 through the blower fan 4, and is emitted into the outer frame 1.
Heat is removed by the outer wall of the drum and the temperature becomes low, which is then heated again by the heat source section 3 and flows into the rotating drum 2.

On the other hand, moisture condensed when the high-temperature, high-humidity air is cooled accumulates on the bottom of the outer frame 1 and is discharged to the outside of the machine body through the drain port 13.

The broken line arrows in FIG. 2 indicate the flow of cooling air. The cold outside air drawn into the partition wall 8 by the cooling fan 5 cools the electric motor 6, and then is guided to the cooling air guide 12. , the upper surface portion of the outer frame 1 and the back cover 10 are cooled, and then released to the outside air again.

However, in the drying device configured to perform the drying operation as described above, the device according to this embodiment has the second and third
As shown in the figure, the height H of the outer frame 1 is 725 mm, the width L is 610 mm, and the outer diameter D of the rotating drum 2 is 575 mm, which is 35 mm smaller than the width L of the outer frame 1, which is 580 mm or less. It is.

This follows what was explained earlier in the explanation of the principle.

As a result, the rotation speed N _D of the rotary drum 2 is approximately 55.8 revolutions per minute from the relationship expressed in equation (2) above.

In the clothes dryer described above, the maximum possible outer diameter of the blower fan 4 was 180 mm.

Now, instead of the electric motor 6 of the clothes dryer mentioned above,
By using a four-pole single-phase induction motor, the rotation speed of the blower fan 4 is 1425 to 1430 revolutions per minute (the rotation speed when the power frequency is 50 Hz and the slip rate is 5% with a four-pole single-phase induction motor). The air volume-pressure characteristic at this time is shown by curve A in FIG.

However, the ventilation resistance at the required air volume was at point B in the figure, and this product could not satisfy that performance.

On the other hand, as in this embodiment, when the electric motor 6 is a two-pole single-phase induction motor with a slip ratio of 20% as described earlier (as described above, the power supply frequency is 50Hz). When the rotation speed is 2400 revolutions per minute), the air volume-pressure characteristics of the fan 4 are as follows:
As shown by curve C in Fig. 4, point B in the figure can be easily satisfied, and even if the outer diameter of the blower fan 4 is further reduced, the performance can be satisfied. 4, the outer frame 1 can also be made smaller.

This electric motor 6 has a power frequency of 60Hz, that is,
It is clear that even better effects can be obtained in the case of 2880 revolutions per minute.

In the case of the electric motor 6 mentioned above, as mentioned above, the outer diameter D of the rotating drum 2 is 575 mm, so the rotation speed of the rotating drum 2 at which the centrifugal force exerted on the clothes balances the gravity is the same as mentioned earlier. By the way, in either case of 50Hz or 60Hz, it is 55.8 revolutions per minute, and this and when the power supply frequency is 50Hz,
Motor rotation speed related to motor 6 with a slip rate of 20%
Since 2400 revolutions per minute, the previous N _D = d/D x N _M
From formula (1), the outer diameter d of the drive pulley 15 is approximately
The diameter is 13.4 mm, which is sufficiently larger than the allowable minimum diameter of 10 mm, and the belt 7 can be driven by a simple and inexpensive belt drive.

Furthermore, when used at a power supply frequency of 60 Hz, the rotational speed of the electric motor 6 is 2880 revolutions per minute, but in the same manner as above, the outer diameter d of the drive pulley 15 is 11.1 mm. Even in this case, the diameter is larger than the minimum allowable diameter to facilitate belt driving.

In the above embodiment, the electric motor 6 has a slip rate of 20
%, but as another example, 3200 revolutions per minute at a power frequency of 60 Hz, which is the upper limit of the rotation speed of the motor, that is, a slip rate of about 11.1%. When using a two-pole single-phase induction motor, the outer diameter d of the drive pulley is approximately 10 mm, which is within the permissible range. When using a two-pole, single-phase induction motor with a power frequency of 50 Hz and 1500 revolutions per minute, that is, a slip rate of 50%, the outer diameter d of the drive pulley is approximately
21.4 mm (approximately 18.9 mm at 1800 revolutions per minute when using a power supply frequency of 60 Hz), which is within a sufficient tolerance range, and both are effective in the same way as the above example. A two-pole single-phase induction motor with a high slip ratio in the range between the upper limit and the lower limit can be adopted as another embodiment.

Further, in the above embodiment, the electric motor 6 is placed at the top so that the air intake port is at the top, but this electric motor may be placed at the bottom.

Furthermore, although the above embodiment is related to a dehumidifying type, for example, an air inlet is provided in front of the blower fan, the air circulates inside the outer frame via the heat source, and an exhaust air provided on the back cover, etc. This can be an exhaust type clothes dryer that exhausts air from the outlet.

〔Effect of the invention〕

According to the present invention, it is possible to provide a small, simple and inexpensive clothes dryer using a belt drive system using a two-pole single-phase induction motor, and which has excellent practical effects. It can be said that it is a new invention.

[Brief explanation of drawings]

Figure 1 is a diagram explaining the principle of the belt drive system, Figure 2
The figure is a longitudinal cross-sectional view of a clothes dryer according to an embodiment of the present invention, FIG. 3 is a cross-sectional view taken along the line X-X in FIG. 2, and FIG. It is a relationship curve diagram showing required air volume-pressure. DESCRIPTION OF SYMBOLS 1...Outer frame, 2...Rotating drum, 3...Heat source part, 4...Blower fan, 6...Electric motor, 7...Belt, 14...Rotating shaft, 15...Driving pulley.

Claims (1)

[Scope of Claims] 1. An outer frame, a rotary drum rotatably supported within the outer frame, a heat source, a blower fan, an electric motor for driving the rotary drum and the blower fan, and an electric motor for driving the rotary drum and the blower fan. A drive pulley provided on the rotating shaft of the electric motor, and a belt that is hung between the drive pulley and the outer periphery of the rotating drum to transmit the rotational force of the electric motor to the rotating drum. The diameter is 580mm or less, and the motor is a two-pole single-phase induction motor.
A clothes dryer characterized in that the motor has a high slip rate, and the rotation speed of the motor is 3200 revolutions per minute or less when the power supply frequency is 60Hz, and the rotation speed of the motor is 1500 revolutions per minute or more when the power supply frequency is 50Hz. 2. In what is stated in claim 1,
Attach the blower fan directly to the rotating shaft of the electric motor,
Or a clothes dryer that is attached to a drive pulley installed on a rotating shaft.