JPS5812013B2 - Vacuum cleaner overheating prevention device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an overheat prevention device for a vacuum cleaner.

Conventionally, in order to prevent overheating due to insufficient cooling of the motor due to insufficient suction airflow due to filter clogging,
When the degree of negative pressure in the negative pressure chamber reaches a certain value, outside air is introduced to ensure the necessary air flow for cooling the motor.

The part that exhibits this function is called a leak valve, and there are various types of leak valves, and the fact that the amount of movement of the valve body is determined according to the degree of negative pressure is used to make the user aware of the clogged state of the filter. There are also types that have the function of an indicator.

The structure of this type of leak valve is that a valve body that moves according to the degree of negative pressure is biased in one direction by a spring and is slidably installed inside a transparent pipe, and when a preset degree of negative pressure is reached, the valve closes. The body is designed to take in outside air by communicating an outside air communication hole formed in a transparent pipe with a negative pressure chamber.
The air passage between them utilizes the gap between the outer periphery of the valve body and the inner periphery of the transparent pipe.

Therefore, due to the dynamic pressure and the viscosity of the air, the leak valve does not exhibit crisp operation, and chattering is likely to occur.

Additionally, since the maximum movement dimension of the valve body is controlled by the length of the spring's tight contact, there is a large variation in that dimension, which can cause the valve body to move excessively and not be able to take in sufficient air in the event of a leak. Become.

Therefore, the stability is poor and it is not possible to obtain the optimum amount of outside air.

The present invention has been made in view of these points, and an object of the present invention is to provide an overheating prevention device for a vacuum cleaner that exhibits stable operation and is capable of obtaining an optimal amount of outside air.

The present invention provides a transparent pipe that has an intake hole formed on an end face and an elongated through hole formed on a side face and communicates with a negative pressure chamber through a ventilation member, and communicates with the through hole within this transparent pipe. The valve body has a long and thin side hole extending in a direction perpendicular to the longitudinal direction of the hole, and the inside of the valve body serves as a ventilation passage.The valve body is slidably biased toward the end surface. That is.

Therefore, when the degree of negative pressure in the negative pressure chamber becomes high and the valve body moves due to the external pressure from the intake hole, and as a result, the through hole and the side hole overlap and the outside air flow is sucked in,
The through hole and the side hole intersect in their longitudinal directions, and
Since the maximum efficiency range of outside air intake is large, the amount of movement of the valve body when the side hole is fully open is large, and this allows it to sufficiently cope with large pressure changes in the negative pressure chamber, resulting in a high degree of negative pressure. The structure is such that chattering is less likely to occur in this state.

Embodiments of the present invention will be described with reference to FIGS. 1 to 3.

First, a negative pressure chamber 3 in which a filter 2 is detachably provided is formed in the front part of the main body 1, and an electric blower chamber 5 for holding an electric blower 4 communicating with the negative pressure chamber 3 is provided in the rear part. There is.

The electric blower chamber 5 communicates with an exhaust hole, although not particularly shown.

Further, a lid 6 is detachably provided on the main body 1, and the lid 6 is formed with a suction hole 7 communicating with the filter 2, and an indicator chamber 8 is formed in the rear part.

A transparent plate 10 is provided on the outer surface of the indicator chamber 8 and is provided with an outside air hole 9 and a zone display (not shown).

Further, a leak valve 12 communicating with the negative pressure chamber 3 is provided in the indicator chamber 8 .

The leak valve 12 consists of a ventilation member 13 whose lower part is fitted with the lid 6, a transparent pipe 14 attached to the ventilation member 13, a valve body 15 that slides inside the transparent pipe 14, and a valve body 15 that slides inside the transparent pipe 14. It consists of a compression spring 16 that biases the spring 15.

One end of the transparent pipe 14 is open, an intake hole 18 of a predetermined diameter is formed in the end surface 17 of the other end, and a side surface 19 is formed.
A long through hole 11 is formed in the longitudinal direction of the transparent pipe 14 at approximately the middle of the transparent pipe 14 .

The valve body 15 is formed into a pipe shape with an outer diameter that allows it to slide smoothly inside the transparent pipe 14 while being prevented from rotating in the circumferential direction by a rotation preventing member (not shown), and has a recess 20 on the end surface 17 side. A side hole 22 is formed on the suction side of the support wall 21 and overlaps with the through hole 11 and is long in the circumferential direction, and the inside thereof is used as a ventilation passage 23.

Furthermore, a stepped portion 24 is formed in the air passage 23, with which one end of the compression spring 16 comes into contact.

Further, a vertical vent hole 25 and a holding hole 26 perpendicular to the vent hole 25 are formed in the ventilation member 13, and the transparent pipe 14 is held by the holding hole 26.

Further, a stopper 27 is formed in a step shape so as to coincide with the portion where the transparent pipe 14 comes into contact and restricts the sliding movement of the valve body 15.

That is, when one end of the valve body 15 is positioned by the stopper 27, the side hole 22 and the through hole 11 are set to have a maximum opening ratio.

This maximum opening ratio occurs before the valve body 15 comes into contact with the stopper 27, and has a predetermined range.

Note that 28 is a projection for positioning the compression spring 16.

In such a configuration, when the electric blower 4 is driven,
Air containing dust flows through the suction hole 7 through a flexible tube (not shown), etc.
It is sucked in by the filter 2, cleaned by the filter 2, cooled by passing through the interior of the electric blower 4, and then discharged from the exhaust hole.

At this time, if the filter 2 is not clogged, the amount of outside air sucked in through the suction hole 7 is large, so the electric blower 4 is sufficiently cooled, and the degree of negative pressure in the negative pressure chamber 3 is not too high, so the valve is closed. Body 15 is also not sucked.

As the filter 2 becomes clogged, the suction airflow from the suction hole 7 decreases, and therefore the flow rate of the cooling air of the electric blower 4 also decreases, and the degree of negative pressure in the negative pressure chamber 3 gradually increases.

As a result, atmospheric pressure is acting on the concave portion 20 side of the valve body 15 via the intake hole 18 and the outside air hole 9, and the pressure inside the negative pressure chamber 3 is acting on the other side, so there is a pressure difference between the left and right sides. This pressure difference causes the valve body 15 to move from the position shown by the dashed line to the position shown by the solid line against the compression spring 16.

Since this amount of movement is related to the degree of negative pressure, the valve body 15 also functions as an indicator to indicate the clogging state of the filter 2 by means of coloring the valve body 15 or the like.

When the degree of negative pressure in the negative pressure chamber 3 reaches a predetermined value or more, the through hole 11 and the side hole 22 begin to overlap, and outside air is sucked in through the ventilation path 23 and the ventilation port 25, and the air is sucked out from the suction hole 7. Even if the amount of outside air is insufficient, a sufficient air flow necessary for cooling the electric blower 4 can be obtained, and overheating thereof can be prevented.

Moreover, since the range of the maximum opening ratio between the through hole 11 and the side hole 22 is quite large, when the degree of negative pressure becomes considerably high, the valve body 15 moves too much and the opening ratio between the through hole 11 and the side hole 22 increases. This eliminates the inconvenience of not being able to obtain the required amount of outside air due to a decrease in the amount of outside air.

In addition, in the process of moving the valve body 15, the outside air flows into the valve body 1.
The valve body 15 passes through the gap between the valve body 15 and the transparent pipe 14, and then passes through the side hole 22 and the ventilation path 23. However, the length of the gap between the valve body 15 and the transparent pipe 14, which is affected by dynamic pressure and air viscosity, is quite long. Since the ventilation path 23 is short and occupies most of the entire length of the valve body 15, it is less affected by dynamic pressure and air viscosity, and as a result, its movement is stable and chattering is less likely to occur.

Further, the compression spring 16 is set so that even when the valve body 15 comes into contact with the stopper 27, the valve body 15 does not come into close contact with the stopper 27.

Further, the formation of the recess 20 on one side of the valve body 15 brings about the following effects.

First, to explain from the state where there is no recess 20, when there is a pressure difference between the outside air and the negative pressure chamber 3, there is a slight gap between the outer periphery of the valve body 15 and the inner periphery of the transparent pipe 14. A small amount of air flows in from 18, creating an airflow through the gap.

As the pressure difference increases, the air flow rate increases, but the velocity head becomes higher in the periphery, and the force pressing against the valve element 15 is weaker than the product of the projected cross-sectional area of the valve element 15 and the static pressure. .

Therefore, the correspondence relationship with the pressure difference is not sensitive.

However, when the pressure difference exceeds a certain value, the fluid resistance in the gap increases rapidly, and the force for pressing the valve element 15 also increases rapidly, pushing the valve element 15 rapidly.

This means that the display of the safe use condition immediately changes to the display of the dangerous use condition, and the performance as an indicator is extremely low.

On the other hand, by providing the recess 20 as described above, static pressure acts stably at least inside the recess 20 without being affected by dynamic pressure, and there is linearity in correspondence with the pressure difference, resulting in safety. It gradually transitions from a usage state to a dangerous usage state, improving its performance as an indicator.

Next, what is shown in FIG. 4 is a modification of the present invention, in which the through hole 1
1 and the side hole 22 are arranged in a direction opposite to that of the previous embodiment.

Even in this case, the operation is the same as that of the previous embodiment.

In the present invention, as described above, the through hole of the transparent pipe that sucks outside air as a leak valve and the side hole of the valve body are formed so that their longitudinal directions intersect with each other, so that the maximum opening ratio of the through hole and the side hole is achieved. Since the range in which the valve body is maintained is large, the amount of movement of the valve body in its maximum opening ratio state is large, and this allows it to sufficiently cope with large pressure changes in the negative pressure chamber. Chattering is less likely to occur in this state, and sufficient suction airflow can be obtained, thereby making it possible to reliably prevent the electric blower from overheating while indicating the clogging state.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view of a vacuum cleaner showing an embodiment of the present invention, FIG. 2 is a vertical side view of an indicator, and FIG.
The figure is a bottom view of a part thereof, and FIG. 4 is a bottom view of a modified example. 3...Negative pressure chamber, 13...Air conditioner member, 14...Transparent pipe, 15...Valve body 17...End face, 18...Intake hole, 19...Side surface, 22... Side hole, 23... ventilation path.

Claims (1)

[Claims] 1. A transparent pipe is provided which has an intake hole formed on an end face and an elongated through hole formed on a side face, and is communicated with a negative pressure chamber through a ventilation member, and a transparent pipe that can communicate with the through hole and is connected to the negative pressure chamber through a ventilation member is provided. A valve body having a long and narrow side hole extending in a direction perpendicular to the longitudinal direction of the through hole and having a ventilation passage inside thereof is provided so as to be biased toward the end face and slidable. Vacuum cleaner overheating prevention device.