JPS5812012B2 - 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 air flow necessary 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 the two is made using 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 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 a passage hole formed on a side face and is communicated with a negative pressure chamber through a ventilation member, and the transparent pipe can communicate with the passage hole. A valve body having a side hole with a ventilation passage inside thereof is biased toward the end face and slidably provided, and the side hole and the through hole are aligned with the transparent pipe or the ventilation member. The present invention is characterized in that a stopper is provided to stop the valve body at the position.

However, if the degree of negative pressure in the negative pressure chamber increases to the point where the through hole and the side hole match, the stopper will regulate the state of matching between the two, making it possible to always maintain the optimum amount of outside air. Furthermore, since the outside air passage is inside the valve body, the valve body is not affected by dynamic pressure or air viscosity, and thus stable operation can be achieved.

A first embodiment of the present invention will be described based on FIGS. 1 and 2.

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. .

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 through hole 11 is formed at a substantially intermediate position.

Further, 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, and the end face 17
It has a support wall 21 in which a recess 20 is formed on the side, and a side hole 2 corresponding to the through hole 11 is provided on the suction side of the support wall 21.
2 is formed, 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 coincide with each other so as to have a maximum opening ratio.

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.

Then, when the degree of negative pressure in the negative pressure chamber 3 reaches a predetermined value or more, the valve body 15 is positioned by the stopper 27, and the through hole 11
The outside air is sucked in through the side hole 22, the ventilation path 23, and the ventilation port 25, and even if the amount of outside air from the suction hole 7 is insufficient, the air flow necessary for cooling the electric blower 4 can be obtained sufficiently. Prevent its overheating.

Therefore, when the degree of negative pressure becomes considerably high, the valve body 15
This eliminates the inconvenience of not being able to obtain the necessary amount of outside air due to excessive movement of the air passage hole 11 and the opening ratio of the through hole 11 and the side hole 22.

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, let us explain from the state where there is no recess 20. When there is pressure 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 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, a second embodiment of the present invention will be described with reference to FIG.

The same parts as in the previous embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In this embodiment, a ring 30 having an opening 21 smaller than the inner diameter of the transparent pipe 14 is fixed to the opening edge side of the transparent pipe 14.
0 as a stopper 27.

The operation is exactly the same as the above embodiment.

4 and 5 is a third embodiment of the present invention, in which two legs 31 are formed at one end of the valve body 15, and these legs 31 are connected to the protrusion 28 of the ventilation member 13. This wall surface 32 is used as a stopper 27 so as to come into contact with the wall surface 32 on the formed side.

In the present invention, as described above, the valve body is movably provided inside the transparent pipe, and the inside of the valve body is used as the ventilation path, so that when the degree of negative pressure in the negative pressure chamber increases, the side hole and the through hole are connected. Even when the valve is in the open state, it is not affected by dynamic pressure or air viscosity, allowing stable operation. Since this is provided, an optimum cooling airflow can always be obtained even when the degree of negative pressure increases.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view of a vacuum cleaner showing an embodiment of the present invention, Fig. 2 is a longitudinal sectional side view of an indicator of the first embodiment of the invention, and Fig. 3 is a second embodiment of the vacuum cleaner. FIG. 4 is a longitudinal side view showing an example, FIG. 4 is a longitudinal side view showing a third embodiment, and FIG. 5 is a perspective view of the valve body. 3... Negative pressure chamber, 13... Ventilation member, 1
4...Transparent pipe, 15...Valve body, 1
7...End face, 18...Intake hole, 19.
...Side side, 22...Side hole, 23...
...Vent passage, 27... Stopper.

Claims (1)

[Claims] 1. A transparent pipe is provided which has an intake hole formed on an end surface and a communication hole formed on a side surface and communicates with a negative pressure chamber through a ventilation member, and a side hole that can communicate with the communication hole is provided in the transparent pipe. and a valve body having a ventilation passage inside thereof is biased toward the end face and slidably provided, and the transparent pipe or the ventilation member is provided at a position where the side hole and the through hole coincide with each other. An overheating prevention device for a vacuum cleaner, characterized in that a stopper for stopping the valve body is provided.