JPS5812015B2 - 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 stands in such a way that the outside air is taken in by communicating the outside air communication hole formed in the transparent pipe with the 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 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 the above points, and an object of the present invention is to provide an overheating prevention device for a vacuum cleaner that exhibits stable operation depending on the pressure difference 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 provided so as to be biased toward the end surface so as to be freely slidable, and a labyrinth effect is created from the side hole of the valve body on the outer circumferential surface in the direction of the intake hole. It is characterized by having an annular groove formed therein.

Therefore, since the groove is formed on the outer circumferential surface of the valve body, the fluid resistance in the gap that inevitably occurs in the sliding part between the valve body and the transparent pipe becomes considerably high due to the labyrinth effect caused by the vortex generated in the groove. As a result, leakage airflow is suppressed, and the valve body moves in a linear manner in response to the pressure difference between the negative pressure chamber and the outside air, thereby ensuring accurate function as an indicator and also as a leak valve. The function is also configured to be able to operate reliably with a preset pressure difference.

Embodiments of the present invention will be described based on the drawings.

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 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
An annular groove 20 is formed on the outer periphery of the side, and a side hole 22 that coincides with the through hole 11 is formed, and an air passage 23 is formed inside the side hole 22 .

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 hole 17
The intake airflow from the electric blower 4 decreases, so the flow rate of cooling air from the electric blower 4 also decreases, and the degree of negative pressure inside 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.
Since it passes through the air passage 23 in the air passage 5, 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 annular groove 20 on the outer circumference of the valve body 15 brings about the following effects.

That is, when a pressure difference occurs between the external pressure and the pressure within the negative pressure degree 3, an air flow is generated in the gap between the valve body 15 and the transparent pipe 14, but the fluid resistance of this gap is This is considerably increased due to the so-called labyrinth effect caused by the eddy current, which suppresses the leakage airflow and causes the compression spring 16 to deflect in accordance with the pressure difference, resulting in a balance with a more or less linear relationship.

This allows the valve body 15 to act as an indicator.
The movement of the indicator corresponds to the pressure difference, and the indicator function becomes stable.

Further, since the pressure difference between the through hole 11 and the side hole 22 is also constant, the timing at which the leak airflow is obtained is stable.

As described above, the present invention forms an intake hole and a through hole in a transparent pipe, and a valve body having a side hole is slidably attached inside the transparent pipe, and the outer peripheral surface in the direction of the intake hole is attached from the side hole. Since the annular groove is formed, the fluid resistance in the gap between the valve body and the transparent pipe becomes considerably high due to the labyrinth resistance created by the groove, which reduces the amount of movement of the valve body due to the pressure difference between the negative pressure chamber and the outside air. This has effects such as having accurate linearity, stabilizing its function as an indicator, and making the timing for starting operation as a leak valve accurate.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal side view, and FIG. 2 is a longitudinal side view of a leak valve. 3... Negative pressure chamber, 13... Venting member, 14... Transparent pipe, 15... Valve body, 17... End surface, 18...
Intake hole, 19... Side surface, 20... Groove, 22... Side hole, 23... Ventilation path.

Claims (1)

[Claims] 1. A transparent pipe is provided which has an intake hole formed on an end surface and a through hole formed on a side surface and is communicated with a negative pressure chamber by a ventilation member, and a side that can communicate with the through hole is provided in the transparent pipe. A valve body having a hole and a ventilation passage inside thereof is biased toward the end face and slidably provided, and an annular groove exhibiting a labyrinth effect is formed on the outer peripheral surface in the direction of the intake hole from the side hole. An overheating prevention device for a vacuum cleaner, characterized in that: