JPS5812016B2 - 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 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.

In addition, 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 dimension1, which causes 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.

Another problem is that there is hysteresis in the movement of the valve body, resulting in low responsiveness to pressure difference fluctuations.

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 communicates with a negative pressure chamber through a ventilation member, and allows communication with the through hole within the transparent pipe. A valve body having a side hole close to the partition wall and having a ventilation passage inside thereof is provided so as to be slidable by biasing it toward the end face, so that the through hole and the side hole coincide with each other. In the above-mentioned state, an outside air introduction part is formed in the through hole and extends in the suction direction.

Therefore, the pressure difference increases and the valve body moves to the suction side,
When the through hole and the side hole coincide and a leak airflow occurs, since the outside air introduction part is formed on the suction side of the through hole, the suction airflow will apply force to the valve body in the direction of return. acts,
As a result, hysteresis is less likely to occur when the pressure difference decreases and the valve body returns, and the movement of the valve body in the direction of return occurs immediately, ultimately allowing the electric blower to operate in the most efficient state. It is configured so that it can be done.

A first embodiment 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. .

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

A lid 6 is detachably provided on the main body 1, and the lid 6 has a suction hole 7 communicating with the filter 2, and an indicator chamber 8 at the rear thereof.

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.

A notch 29 is formed on the suction side of the through hole 11 to serve as an outside air introduction section.

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 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 through the intake hole 18 and the outside air hole 9, and the pressure inside the negative pressure chamber 8 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.

As the pressure difference between the outside pressure and the pressure inside the negative pressure chamber 3 increases, the valve body 15 moves to the left against the compression spring 16, but the side hole 22 and the through hole 11 Since the notch 29 exists in the through hole 11 when the pressure difference decreases compared to the pressure difference when they match, the pressure difference when the valve body 15 moves in the return direction is not so large.

To give an actual example, in a water column with a maximum power of 130 W and a pressure H in the negative pressure chamber of 700 to 750 mm, the valve body 1
When the pressure in the negative pressure chamber 3 decreases so that the side hole 22 and the through hole 11 coincide with each other, the negative pressure chamber 3
The pressure is 1000 mm water column.

When the pressure inside the negative pressure chamber 3 rises and the valve body 15 returns, the pressure inside the negative pressure chamber 3 is 500 mm water column when the notch 29 is not provided, and when the notch 29 is present, the pressure inside the negative pressure chamber 3 is 500 mm water column. 800-900mm water column.

Therefore, when the notch 29 does not exist, the hysteresis is large, and when the notch 29 exists, the hysteresis is small.

The reason why such a phenomenon occurs is considered to be as follows.

In other words, the cause of hysteresis is thought to be sliding friction or other mechanical causes, but without the notch 34, the through hole 1
1 and the side hole 22 into the ventilation passage 23, and when the outside air flow decreases, no dynamic pressure is applied to the valve body 15. However, by providing the notch 29, the outside air flow is reduced. This means that dynamic pressure is applied to the support wall 21 of the valve body 15 in the right direction, and this dynamic pressure allows smooth starting in the return direction.

The small hysteresis with respect to the movement of the valve body 15 has two advantages.

First, in a vacuum cleaner performance test, the power is measured when the filter 2 gradually becomes clogged, and the power is measured when the suction hole 7 is gradually opened from a blocked state. In this case, the measured values in either case are not affected by the leakage airflow and there is no significant difference, and an accurate performance test can be performed.

Next, during use, when cleaning a carpet or when a large piece of paper sticks to it, the negative pressure inside the negative pressure chamber 3 increases momentarily, and the valve body 15 moves to the left end, but the hysteresis If it is large, the valve body 15 will not easily return even if such a state is resolved, and cleaning will continue in a state where outside air suction efficiency is poor, resulting in a decrease in suction efficiency.

In addition, in this state, the valve body 15 is in a dangerous use state, so even though it is in a state where there is no need to dispose of dust under the illusion that the filter 2 is clogged,
You will be forced to do extra work.

Such inconveniences can be solved simply by providing the notches 29.

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, a second embodiment of the present invention will be described based on FIGS. 4 and 5.

In this embodiment, a semicircular arc portion 30 is formed on the suction side of the through hole 11 as an outside air introducing portion.

This arcuate portion 30 is formed as a taper that opens outward.

Therefore, this arcuate portion 30 exhibits the same effect as in the previous embodiment.

The present invention provides a structure in which a valve body is movably provided in a transparent pipe having a through hole as described above, and a side hole is provided in this valve body that overlaps with the through hole, and outside air is introduced into the suction side of the through hole. Because of the provision of a section, when the valve body moves and the through hole and side hole overlap and a leak airflow occurs, a component force is generated that presses the valve body in the return direction, thereby separating the negative pressure chamber from the outside air. When the pressure difference tends to decrease, the valve body begins to move in the return direction, which has the effect of allowing an accurate performance test to be performed and efficient cleaning. .

[Brief explanation of drawings]

Fig. 1 is a partially cutaway side view of the vacuum cleaner, Fig. 2 is a longitudinal sectional side view showing the first embodiment of the present invention, Fig. 3 is a bottom view of the part, and Fig. 4 is the main body of the vacuum cleaner. FIG. 5 is a longitudinal sectional side view of a portion of the second embodiment of the invention, and FIG. 5 is a rear view thereof. 3... Negative pressure chamber, 13... Venting member, 14... Transparent pipe, 15... Valve body, 17... End surface, 18...
Intake hole, 19...side surface, 21...partition wall, 22...
Side hole, 23... Ventilation path, 29... Notch (outside air introduction part), 30... Arc part (outside air introduction part).

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. A valve body having a valve body close to the partition wall and having a ventilation passage inside thereof is provided so as to be slidable by biasing it toward the end surface, and when the through hole and the side hole are aligned, the valve body has a vent passage inside. An overheating prevention device for a vacuum cleaner, characterized in that an outside air introduction part extending in the suction direction is formed in a through hole.