JPS5812017B2 - 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. This is a type of indicator that functions as an indicator.

The structure of this type of leak valve is that it is slidably installed inside a transparent pipe and is biased in one direction by a spring that moves according to the degree of negative pressure, 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 air, the leader 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 through hole formed on a side face, and is communicated with a negative pressure chamber through a ventilation member, and a ventilation path with one end opened inside is provided. A valve body having an annular groove formed on its outer periphery and a side hole communicating with the air passage within the annular groove is provided in the transparent pipe so as to be able to slide freely while being biased toward the end surface. It is characterized by:

Therefore, even if the valve body sliding in the transparent pipe rotates in the circumferential direction, the annular groove is formed in the valve body, so communication between the through hole and the side hole is always achieved. Accordingly, the structure is such that leak airflow can be reliably obtained at a predetermined position simply by alignment in the sliding direction.

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 port, 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, and an intake hole 18 of a predetermined diameter is formed in the side surface 17 of the other end, and the side surface 19
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 supporting wall 21 in which a recess 20 is formed on the side thereof, and an annular groove 29 that coincides with the through hole 11 is formed on the suction side of this supporting wall 21, and a side hole 22 is formed in this annular groove 29. The inside thereof is 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 ventilation hole 25 and a holding hole 26 perpendicular to the ventilation hole 25 are formed in the passage 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 air intake 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, and 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 annular groove 29, the side hole 22, the ventilation passage 23, and the ventilation port 25, and even if the amount of outside air from the intake hole 7 is insufficient, the airflow necessary to cool the electric blower 4 is sufficient. obtained and prevents 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.

Moreover, although the valve body 15 is easily movable in the circumferential direction within the transparent pipe 14, since the annular groove 29 exists, the side hole 2
2 may be in any direction.

In addition, in the process of moving the valve body 15, the outside air 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 recess 20 on one side of the valve body 15 brings about the following effects.

First, to explain the state without the 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 through the gap, creating an airflow.

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.

In the present invention, as described above, a valve body is slidably provided in a transparent pipe provided with a through hole, and a ventilation portion is formed in the valve body, as well as an annular groove having a side hole. Leader airflow can be reliably generated even if the valve body, which responds to the pressure difference between the chamber and the outside air, rotates in the circumferential direction.
Thereby, the function of the indicator and the function of the leak valve can be stabilized.

[Brief explanation of drawings]

An embodiment of the present invention is shown in the drawings, in which Fig. 1 is a partially cutaway side view, Fig. 2 is a longitudinal side view of the leak valve, and Fig. 3 is a side view showing the state in which the valve body is rotated. It is. 3... Negative pressure chamber, 13... Ventilation member, 1
4...Transparent pipe, 15...Valve body, 1
7...End face, 18...Intake hole, 19...
... Side surface, 22 ... Side hole, 23 ... Air passage, 29 ... Annular groove.

Claims (1)

[Claims] 1. A transparent pipe is provided which has an intake hole formed on the end surface and a through hole formed on the side surface and communicates with the negative pressure chamber through a ventilation member, and a ventilation path with one end open inside is formed and the outer periphery is A valve body having an annular groove formed therein and a side hole communicating with the air passage within the annular groove is provided in the transparent pipe so as to be able to slide freely while being biased toward the end surface. Vacuum cleaner overheating prevention device.