JPH0722180Y2 - Vacuum cleaner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an electric vacuum cleaner having a safety valve device for introducing outside air into an electric vacuum cleaner body for cooling an electric blower.

<Prior Art> A safety valve device for guiding outside air into a conventional electric vacuum cleaner body to cool an electric blower has a flat upper surface in contact with the outside air of the safety valve.

When the pressure (static pressure) is applied to the upper surface of the safety valve, and the difference between the static pressure and the negative pressure inside the vacuum cleaner body becomes the pressure that overcomes the elastic force of the coil spring pushing up the safety valve, the safety valve Moves downward and air flows out through the safety valve device. Although the pressure difference between the static pressure and the negative pressure becomes small due to the inflow of air, the area on which the pressure is applied reaches the entire upper surface of the safety valve, and the force for lowering the safety valve increases, and the safety valve is suddenly pushed down to the bottom of the safety valve device.

At this time, the amount of inflowing air greatly increases and the pressure difference due to static pressure decreases, but the pressure (dynamic pressure) due to the collision of air with the safety valve increases, and the resultant force exceeds the pushing force of the coil spring. With power, the safety valve remains fully open.

<Problems to be solved by the invention> However, in recent years, the performance of vacuum cleaners has improved, and there is a tendency to increase vacuum pressure due to fluid loss, noise, and the adoption of filters with narrow meshes. It is also necessary to increase the operating pressure of the safety valve device. Has occurred. That is, the operating pressure of the safety valve device is increased by increasing the pushing pressure of the coil spring.

However, due to the strength of the coil spring, after the safety valve has fully opened, the combined force of the dynamic pressure and static pressure is lost by the elastic force of the coil spring, and the safety valve is in a half-open state or in an unstable state.
The phenomenon that the safety valve oscillates up and down occurs, and with the safety valve of the conventional size, increase in operating pressure could not be expected so much.

Therefore, to increase the dynamic pressure after the safety valve is opened, increasing the safety valve area allows the safety valve to have a large operating pressure, but it is restricted in terms of space, and the conventional safety valve with a flat upper surface increases the operating pressure. That is, when maintaining or increasing the amount of inflowing air, there is a problem that it is not very efficient.

In view of the above, it is an object of the present invention to provide an electric vacuum cleaner that is compatible with downsizing of the electric vacuum cleaner body and that can ensure safety even when the vacuum pressure is increased.

<Means for Solving the Problem> The means for solving the problem according to the present invention is, as shown in FIGS. 1 and 2, a mechanism having an electric blower body, a dust collecting chamber for detachably storing a dust collecting bag, and an electric blower. A chamber and a communication port that connects the mechanism chamber and the dust collection chamber to each other, and a ventilation path that communicates the space between the dust collection bag and the mechanism chamber to the outside of the main body is formed in the dust collection chamber, In a vacuum cleaner provided with a safety valve device for introducing outside air into the space when the space has a negative pressure above a certain level due to clogging of a dust collecting bag in the ventilation path, A safety valve that opens and closes the passage, and a compression coil spring that biases the safety valve in the closing direction, and the outside air contact surface of the safety valve is formed in a bowl-shaped recess for increasing the operating pressure of the safety valve device. The compression coil spring is brought into contact with the periphery of the back surface.

<Operation> In the above means for solving problems, when the electric blower 4 is driven to suck air from the dust collection chamber 3 and the inside of the dust collection chamber 3 is in a negative pressure state, the safety valve 10 vents the safety valve 10. The road 8 is blocked.

Then, the dust is accumulated in the dust bag 2 and is clogged, so that the inside of the space portion 7 between the dust bag 2 and the mechanism chamber 5 becomes negative pressure. When the pressure difference between the inside and the outside of the space 7 increases and the pressure difference increases more than the elastic force of the compression coil spring 11, the safety valve 10 pushes down the compression coil spring 11 a little and the air enters the space 7. It begins to flow.

Although the pressure difference decreases a little when air flows in, the dynamic pressure due to the collision of air and the static pressure applied to the upper surface of the safety valve 10 are applied to the entire upper surface of the safety valve 10, and the resultant force between the dynamic pressure and the static pressure becomes larger, Press down the safety valve 10 rapidly. When the safety valve 10 goes down to the bottom, the pressure difference decreases due to the air inflow, but the dynamic pressure increases and the upper surface is scooped into a hemispherical shape, so the resultant force becomes larger and the compression coil spring 11 is continuously pushed. Then, the outside air sufficient to cool the electric blower 4 is introduced.

Therefore, by forming the outside air contact surface 10a of the safety valve 10 in a concave shape, more dynamic pressure than before can be obtained when the valve is opened, the elastic force of the compression coil spring 11 can be increased, and the operating pressure is stable. The safety valve device 9 that can secure the amount of inflowing air is obtained. Further, the shape of the safety valve device does not need to be particularly large, and the cleaner body can be downsized.

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings. First
FIG. 1 is a sectional view of a safety valve device showing an embodiment of the present invention, and FIG. 2 is a schematic sectional view of an electric vacuum cleaner equipped with the safety valve device.

As shown in FIG. 2, the electric vacuum cleaner of this embodiment has a dust collecting chamber 3 in which the dust collecting bag 2 is detachably housed in the electric vacuum cleaner body 1, a mechanism chamber 5 having an electric blower 4, and the mechanism. Chamber 5 and dust collection chamber 3
And a communication port 6 for communicating with the dust collection chamber 3 is formed, and a ventilation passage 8 for communicating the space portion 7 between the dust collection bag 2 and the mechanism chamber 5 to the outside of the main body is formed in the dust collection chamber 3. Further, there is provided a safety valve device 9 for introducing outside air into the space 7 when the space 7 becomes negative pressure above a certain level due to clogging of the dust bag 2.

As shown in FIG. 1, the safety valve device 9 includes a safety valve 10 that opens and closes the air passage 8 and a compression coil spring 11 that biases the safety valve 10 in the closing direction. 10a is formed in a concave shape to increase the operating pressure of the safety valve device 9.

A dust collection chamber 3 is formed in the front portion of the electric vacuum cleaner body 1, and a mechanism chamber 5 is formed in the rear portion of the dust collection chamber 3 via a communication port 6. A filter 12 made of porous sponge or the like for removing fine dust contained in dust contained in the air is provided on the front surface of the communication port 6.

The dust collecting chamber 3 is formed so that its upper surface is open, and a main body cover 13 is arranged at the upper surface opening portion of the dust collecting chamber 3. A rear portion of the main body lid 13 is rotatably attached to a panel 14 fixed to the main body 1 about a shaft 15, and a clamp 17 swinging about a shaft 16 is provided on a front portion of the main body cover 13. To be The clamp 17
The locking portion 18 engages with the engaged piece 19 projecting from the main body 1 to prevent the main body lid 13 from being opened accidentally. Clamp 17
Is constantly urged in the locking direction by a clamp spring 20 which is a compression spring.

On the other hand, a suction hose (not shown) is provided at the center of the main body cover 13.
A suction port 21 into which the end portion of is inserted is formed, and in the suction port 21,
A shutter (22) is provided that slides and closes the suction hose when it is removed. A back lid 24 is fixed to the back side of the main body lid 13 via a lid packing 23, and a suction pad packing 25 is attached to a portion of the back lid 24 corresponding to the suction port 21.

The mechanism chamber 5 has a suction port 21, a dust collection chamber 3, and an exhaust port 26.
The electric blower 4 that forms the air flow to the.

The dust bag 2 is arranged inside the dust chamber 3. The dust-collecting bag 2 is composed of a dust-collecting bag main body 27 which is made of a material having air permeability for collecting dust and the like, and an edge member 28 fixed to an opening of the dust-collecting bag main body 27. An intake port 29 having substantially the same shape as that of the suction port 21 is formed in the central portion of the rim member 28, and the periphery of the intake port 29 is in contact with the suction port packing 25.

The space portion 7 is a space formed inside the dust collection chamber 3 and outside the dust collection bag 2. The ventilation passage 8 includes the main body 1
From the vent hole 30 provided on the upper surface of the container to the space 7 through the safety valve device 9 provided on the back cover 24.

The safety valve device 9 includes the safety valve 10 and a compression coil spring.
11, and a valve case 31 into which the safety valve 10 is vertically movably fitted,
A holding body 32 for holding the valve case 31.

The safety valve 10 has a cylindrical shape with an open lower surface, and a hemispherical recess 33 is provided on the side of the outside air inflow direction A at the center of the upper surface 10a that contacts the outside air.

Here, the force (resistance) D exerted on the object in the fluid by the fluid is expressed by the following equation.

D = 1 / 2CdρV ² S (1) where D = resistance (kg), Cd = drag coefficient, ρ = density (kg)
・ S ² / m ⁴ ) (0.1229 with dry air at 20 ° C), V = flow velocity (m
/ s), S = projected area (m ² ) perpendicular to the fluid.

The drag coefficient Cd has the following values experimentally.

Vertical flat plate 1.17, hexahedron 1.05, sphere 0.47, hollow hemisphere (upstream concave) 1.42, sky hemisphere (upstream upstream) 0.42.

That is, the shape of the conventional safety valve 10 is a shape close to a cylinder or a hexahedron, and Cd is close to 1. However, in this embodiment, by providing the recess 33 as large as possible on the contact surface 10a of the safety valve 10 with the outside air. , Cd can be made close to 1.4 (hollow hemisphere), and the dynamic pressure obtained when the safety valve is opened can be made to be 40% higher than before.

The valve case 31 has a cylindrical shape with an open upper surface,
A vertically long side hole 34 is formed on the side surface, a lower portion of the side hole 34 communicates with the dust collection chamber 3, and a bottom hole 35 is formed on the bottom surface. Further, the lower end of the compression coil spring 3 is fitted in the recess 36 formed on the bottom surface, and the upper end of the compression coil spring 3 is in contact with the periphery of the recess 33 of the upper surface 10a.

The holding body 32 is a rubber cylinder whose lower surface is open, and has an opening 37 for allowing outside air to flow into the upper surface thereof.
An engaging portion 38 protruding outward is formed on the side surface. Then, the engaging portion 38 is closely fitted to the projecting piece 24a provided in a ring shape on the back cover 24, and the air passage 8 and the dust collecting chamber 3 are shielded to enhance airtightness. .

In the above structure, the dust collection chamber 3 is driven by driving the electric blower 4.
Air is sucked out from the inside, and the inside of the dust collection chamber 3 becomes a negative pressure state,
Air containing dust is sucked through the suction port 21. Then, the dust is collected in the dust collecting bag 2, and the air is exhausted from the exhaust port 26 through the communication port 6.

At this time, the safety valve device 9 is biased by the compression coil spring 11 in the direction in which the safety valve 10 closes the air passage 8, and the safety valve 10 is in a state of being sealed with the valve case 31.

Then, the dust is accumulated in the dust bag 2 and is clogged, so that the inside of the space portion 7 between the dust bag 2 and the mechanism chamber 5 becomes negative pressure. Then, the pressure difference between the inside and the outside of the space portion 7 increases, and the product value of the pressure and the area of the side hole 34 (the resultant force of the vertical pressure is the same whether the shape of the safety valve is flat or hemispherical). )
Is greater than the elastic force of the compression coil spring 11, the safety valve
10 is the compression coil spring 11 is pushed down a little, the side hole 34 and the valve case
The openings 37 of 31 communicate with each other, and air starts to flow from the ventilation hole 30 to the space 7.

When air flows in, the pressure difference decreases a little, but the pressure acting on the safety valve 10 is applied to the entire upper surface, the combined force of the dynamic pressure and the static pressure due to the collision of air becomes larger, and the safety valve 10 is pushed down abruptly. When the safety valve 10 is lowered to the bottom, the side hole 34 reaches the maximum opening amount and the air passage area becomes the maximum, and the pressure difference decreases due to the air inflow, but the dynamic pressure increases due to the air collision, and the upper surface is hemispherical. Since it is scooped out, the drag force is larger than the conventional one, and the resultant force is larger and the compression coil spring 11 is continuously pushed. Then, the outside air sufficient to cool the electric blower 4 is introduced.

Therefore, by providing the recess 33 on the outside air contact surface 10a of the safety valve 10, more dynamic pressure than before can be obtained when the valve is opened, the elastic force of the compression coil spring 11 can be increased, and the operating pressure is high and stable. The safety valve device 9 that can secure the amount of inflowing air is obtained. Further, the shape of the safety valve device does not need to be particularly large, and the cleaner body can be downsized.

It should be noted that the present invention is not limited to the above embodiments, and it goes without saying that many modifications and changes can be made to the above embodiments within the scope of the present invention.

<Effect of Device> As is clear from the above description, according to the present invention, the space formed between the dust collecting chamber, the dust collecting bag, and the mechanism chamber has a negative value of a certain value or more due to clogging of the dust collecting bag. A safety valve device that introduces outside air into a space when pressure rises consists of a safety valve that opens and closes a ventilation path of the space and a compression coil spring that biases the safety valve in a closing direction. Has a concave shape to increase the operating pressure of the safety valve device,
When the valve is opened, more dynamic pressure than before can be obtained, and a safety valve device with a high operating pressure and a stable inflow air amount can be obtained. Further, the shape of the safety valve device does not need to be particularly large, and the cleaner body can be downsized. Moreover, the operating pressure is evenly applied to the entire coil spring that is in contact with the periphery of the back surface of the recessed portion, a stable opening operation of the safety valve can be obtained, and the safety valve device can be operated reliably.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a safety valve device showing an embodiment of the present invention, and FIG. 2 is a schematic sectional view of an electric vacuum cleaner equipped with the safety valve device. 1: Vacuum cleaner body, 2: Dust collection bag, 3: Dust collection chamber, 4: Electric blower, 5: Mechanism room, 7: Space part, 8: Ventilation passage, 9: Safety valve device, 1
0: Safety valve, 10a: Outside air contact surface, 11: Compression coil spring.

Claims (1)

[Scope of utility model registration request] 1. A main body of the electric vacuum cleaner is provided with a dust collecting chamber in which a dust collecting bag is detachably accommodated, a mechanism chamber having an electric blower, and a communication port for connecting the mechanism chamber and the dust collecting chamber. A ventilation path is formed in the dust collection chamber to connect the space between the dust collection bag and the mechanism chamber to the outside of the main body, and the space has a certain negative pressure due to clogging of the dust collection bag. In a vacuum cleaner provided with a safety valve device that introduces outside air into the space when it becomes, the safety valve device includes a safety valve that opens and closes the ventilation passage, and a compression coil spring that biases the safety valve in a closing direction. The vacuum cleaner characterized in that the outside air contact surface of the safety valve is formed in a bowl-shaped recess for increasing the operating pressure of the safety valve device, and the compression coil spring is brought into contact with the periphery of the back surface of the recess. .