KR20190102968A - Hermetically sealed housing - Google Patents

Abstract

The present invention relates to a hermetically sealed housing and, more specifically, to a hermetically sealed housing to improve efficiency by realizing the shape of a boundary surface suitable for a hermetically sealed structure where internal pressure is lower than external pressure based on a boundary surface dividing the exterior and the interior. The present invention realizes an optimal housing shape in accordance with internal and external pressure differences to minimize friction by a fluid (air) rapidly lost by a speed increase of a rotary body (rotor, bearing, etc.) to be structurally sturdy by a lower stress level and a more uniform stress distribution than a conventional hermetically sealed housing. The thickness of a boundary surface can be manufactured to be thinner than a conventional technique. A low-strength material can be used. Spatial disadvantages of a conventional convex housing can be resolved. More spare space can be secured by spatial advantages which are better than a conventional flat housing.

Description

Hermetically sealed housing

The present invention relates to a hermetic housing, and more particularly to a hermetic housing for improving efficiency by implementing a shape of an interface suitable for a hermetic structure having an internal pressure lower than an external pressure based on an interface separating the inside and the outside. It is about.

Because it is difficult to accurately predict the supply and demand of power, energy storage is needed for efficient energy management.

In the case of power generation by generating heat such as thermal power generation and nuclear power generation, it is most economic to maintain a constant output. On the other hand, in the case of power generation using natural power, such as hydroelectric power, wind power, and solar power, the output depends on the natural environment such as the season, while the demand for power is natural such as day, night, and season changes. It is changed by various factors such as changes in the environment, operation of large-scale factories and transmission accidents.

Due to the nature of power energy, which consumes and supplies at the same time, it is expensive to adjust power equipment to the maximum demand, and equipment and manpower necessary for control are needed to adjust the output according to demand.

In the output fluctuation process, the lifespan of the power generation equipment is shortened, and a small mismatch between the quantity of supply and the quantity of supply causes a lot of problems.

In order to solve this problem, various types of power storage technologies have been developed.

Conventional energy storage technologies currently in use or under development include pumping power generation technology, compressed air storage energy storage technology, battery energy storage technology, superconducting magnetic energy storage technology, flywheel energy storage technology and the like.

Flywheel Energy Storage System (Flywheel Energy Storage System) of the device for implementing such a technology uses the surplus power to rotate the motor at this time to store the inertial energy of the attached rotating body, if necessary converts back to electrical energy Device to use.

Advantages of such a flywheel energy storage device include better energy storage efficiency, instant charging and discharging, longer energy life, and no degradation at low temperatures compared to conventional mechanical and chemical energy storage devices.

Due to the characteristics of these devices, electric vehicles are currently used in various fields from the private sector to the military sector such as auxiliary power sources, uninterruptible power supplies, pulse power generators, and satellites.

Flywheel Energy Storage System (Flywheel Energy Storage System) is a flywheel rotor (rotor) that stores the inertial energy generated during rotation, the motor for driving the flywheel rotor (rotor), the generator for generating power, the input and output of power As a controller to control and peripheral accessories, it consists of a magnetic bearing part and a housing part.

That is, a flywheel energy storage system (Flywheel Energy Storage System) is one of the devices that are recently attracting attention as a means for storing energy.

The flywheel energy storage device is a device that converts electrical energy input into rotational kinetic energy of a flywheel, stores it, and outputs it back to electrical energy when needed, which is one of high efficiency, pollution-free mechanical energy storage devices.

The flywheel energy storage device is a flywheel for storing high-speed rotational energy, and a flywheel for storing energy, and electric power for generating electricity from the change of magnetic force due to the rotation of the flywheel when the flywheel is rotated because electric power is required. It consists of a generator.

In addition, the flywheel energy storage device configured as described above includes a power converter as a means for converting the generated electricity into high speed and high efficiency. The flywheel energy storage device includes a housing or a vacuum chamber of a predetermined vacuum space to minimize resistance friction due to inertial force. It is installed inside.

Flywheels, on the other hand, generally consist of a relatively heavy mass mounted on the shaft and adapted to rotate with the shaft.

It is also known to convert the kinetic energy of the flywheel into electrical energy by using the flywheel for energy storage.

The kinetic energy of the flywheel is directly proportional to the square of the rotational inertia and angular velocity. Flywheels used for vehicle energy storage must have an optimal balance of mass, inertia, and rotational speed.

Typically, high speed flywheels are incorporated inside a vacuumed housing to reduce energy losses caused by drag and to prevent the flywheel from rising as a result of friction with ambient air. It is.

As such, since the flywheel is a method of storing energy by rotating the rotor in a housing, it is very important to minimize energy loss during rotation.

Therefore, there is a demand for how to maintain the inside of the housing (or chamber) in a vacuum state in order to minimize the friction caused by the fluid (air) that is rapidly lost as the speed of the rotor (rotor, bearing, etc.) increases, and the internal and external pressure An optimal housing shape for the car is inevitably required.

Korean Patent Registration No. 10-0960785, titled 'Large capacity hollow flywheel power storage device' (Registration date 2010.05.24.)

The present invention has been made to meet the above-mentioned needs, and based on a boundary that separates the inside from the outside, the sealed housing which can improve the efficiency by implementing the shape of the boundary surface suitable for the closed structure in which the internal pressure is lower than the external pressure. The purpose is to provide.

In order to solve the above problems, the hermetic housing (housing) according to an embodiment of the present invention is a device that is sealed inside,

An upper surface of a predetermined thickness,

A lower surface portion having a predetermined thickness spaced apart from the upper surface portion by a predetermined distance, and

Wherein the circumference of the upper surface portion and the circumference of the lower surface portion is made to include a side portion of a predetermined thickness forming a surface,

The interior is a space formed surrounding the upper surface portion, lower surface portion and the side portion,

When the pressure of the inner space is lower than the pressure outside the housing, the upper and lower surfaces are lowered to lower the stress and to uniform the stress distribution than when the upper and lower surfaces are convex toward the exterior of the housing. Each of the parts is formed to be concave into the inner space at a predetermined curvature.

The hermetic housing proposed by the present invention has a lower structural stress level and a uniform stress distribution than the conventional hermetic housing.

In addition, there is an advantage that the thickness of the interface can be made thinner than conventional and that a material having a lower strength than the conventional one can be used.

In addition, the hermetic housing (housing) proposed in the present invention has the advantage that can be installed in the same size and shape of the space than the conventional flat housing than the conventional convex housing.

In addition, not only to solve the spatial disadvantage of the conventional convex housing, but also superior to the spatial advantages of the conventional flat housing has the advantage of ensuring the free space.

1 is a conceptual diagram illustrating a typical flywheel energy storage system.
2 to 4 are exemplary views for explaining the housing (housing) proposed by the present invention.
FIG. 5 is an exemplary view illustrating shapes and comparative shapes of a hermetic housing according to the first embodiment of the present invention.
FIG. 6 is a diagram illustrating a finite element method (FEM) applied to shapes and comparative shapes of a hermetic housing according to a first embodiment of the present invention.
FIG. 7 is a test result data diagram of a case of thickness of 7.5 mm for shapes of comparative housings and comparative shapes according to the first embodiment of the present invention.
FIG. 8 is an experimental data diagram of a thickness of 10.0 mm with respect to shapes and comparative shapes of a sealed housing according to a first embodiment of the present invention.
FIG. 9 is an experimental data diagram of a thickness of 12.5 mm with respect to shapes and comparative shapes of a hermetic housing according to a first embodiment of the present invention.
FIG. 10 is an experimental data diagram of a thickness of 15.0 mm with respect to shapes and comparative shapes of a hermetic housing according to the first embodiment of the present invention.
FIG. 11 is a diagram illustrating a finite element method (FEM) applied to shapes and comparative shapes of a hermetic housing according to a second embodiment of the present invention.
12 is a test result data diagram of a case of thickness 10.0mm for the shape of the sealed housing (housing) according to the second embodiment of the present invention and the comparative shapes.
FIG. 13 is a diagram illustrating a finite element method (FEM) applied to shapes and comparative shapes of a hermetic housing according to a third exemplary embodiment of the present invention.
FIG. 14 is an experimental data diagram of a thickness of 10.0 mm with respect to shapes and comparative shapes of a hermetic housing according to a third exemplary embodiment of the present invention.
FIG. 15 is an enlarged view of a part of the experimental data in the case of a thickness of 10.0 mm with respect to the shape of a hermetic housing according to the third embodiment of the present invention.
FIG. 16 and FIG. 17 are enlarged views of experimental data of a case of thickness of 10.0 mm for shapes for comparing with shapes of a closed housing according to a third embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite. As used herein, the term "comprising" embodies a particular characteristic, region, integer, step, operation, element, and / or component, and other specific characteristics, region, integer, step, operation, element, component, and / or group. It does not exclude the presence or addition of.

Unless defined otherwise, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. Commonly defined terms used are additionally interpreted to have a meaning consistent with the related technical literature and the presently disclosed contents, and are not interpreted in an ideal or very formal sense unless defined.

The embodiments of the present invention described with reference to the drawings specifically illustrate an ideal embodiment of the present invention. As a result, various modifications of the drawings are expected. Thus, embodiments are not limited to the specific forms of the illustrated areas. Areas shown or described as flat may have characteristics that are generally rough and / or non-linear.

Also, portions shown to have sharp angles may be rounded. Accordingly, the regions shown in the figures are only approximate in nature, and their forms are not intended to depict the exact form of the regions, nor are they intended to narrow the scope of the invention.

It is noted that the figures are schematic and not drawn to scale. The relative dimensions and ratios of the parts in the figures have been exaggerated or reduced in size for clarity and convenience in the figures and any dimensions are merely exemplary and not limiting. And the same structure, element, or part that appears in more than one figure is the same reference numeral used in different embodiments to indicate corresponding or similar features.

The present invention relates to a hermetic housing for realizing a shape of an interface suitable for a hermetic structure having an internal pressure lower than an external pressure based on an interface separating the inside and the outside, thereby improving efficiency, and energy loss due to friction and the like. It provides an optimal housing shape that minimizes the cost and facilitates manufacturing convenience and efficiency.

Here, a housing means the box-shaped part which surrounds a mechanical apparatus, such as the box-shaped part which accommodates a component (or member), and the frame which embraces a mechanism.

FIG. 1 is a conceptual diagram illustrating a general flywheel energy storage system, and FIGS. 2 to 4 are exemplary views for explaining a housing proposed by the present invention, and FIG. Exemplary drawings showing shapes and comparative shapes of a hermetic housing according to the first embodiment.

FIG. 6 is a diagram illustrating a finite element method (FEM) applied to shapes and comparative shapes of a hermetic housing according to a first embodiment of the present invention, and FIG. 7 is a hermetic type according to a first embodiment of the present invention. Fig. 8 shows experimental data of the thickness of the housing and the comparative shapes of the housing, and FIG. 8 is a thickness of 10.0 for the shapes and the comparative shapes of the sealed housing according to the first embodiment of the present invention. FIG. 9 is an experimental data diagram of the case of mm, and FIG. 9 is an experimental data diagram of the thickness of 12.5 mm with respect to the shape and comparative shapes of the hermetic housing according to the first embodiment of the present invention. FIG. Fig. 1 shows experimental data of a case of thickness 15.0 mm for the shape of the sealed housing according to the first embodiment of the present invention and the comparative shapes.

FIG. 11 is a diagram illustrating a finite element method (FEM) applied to shapes and comparative shapes of a sealed housing according to a second embodiment of the present invention, and FIG. 12 is a sealed type according to a second embodiment of the present invention. Fig. 1 shows experimental data of the case of thickness 10.0 mm for the shape of the housing and the comparative shapes.

FIG. 13 is a diagram illustrating a finite element method (FEM) applied to shapes and comparative shapes of a hermetic housing according to a third embodiment of the present invention, and FIG. 14 is a hermetic type according to a third embodiment of the present invention. Experimental data of the case of thickness 10.0mm for the shape of the housing (housing) and comparative shapes, Figure 15 is an experiment of the case of thickness 10.0mm for the shape of the sealed housing (housing) according to a third embodiment of the present invention 16 and 17 are enlarged views of the result data, and FIGS. 16 and 17 are enlarged views of the test result data when the thicknesses of the shapes for comparing the shapes of the sealed housing according to the third embodiment of the present invention are 10.0 mm.

Introduction

The ever-increasing demand for energy and the increasing number of vehicles that emit toxic fumes are in stark contrast to the challenges of climate change and growing environmental awareness in our society.

As a result, there is an increasing demand for improved technologies in the areas of energy storage, renewable energy and effective driving technologies. This development is an important catalyst for developing new technologies and innovative production processes in this area.

In addition, new technologies face many challenges because of the variety of applications that can be applied. Other techniques must be considered depending on the time the energy is to be stored and the number of charges and discharges.

Another revolutionary technology, called the flywheel energy storage system, is now in the spotlight for energy storage. Fixed and mobile systems are used for different applications.

For example, fixed flywheel systems are used as uninterruptible power supplies (UPSs) in data storage centers and hospitals. Grid balancing tasks, which are increasingly important due to increased use of solar and wind power, can also be supported by flywheel systems.

This technology is an ideal choice for such applications because of its long lifespan in the face of many load cycles and the ability to provide stored energy immediately when needed.

While the basic principles of energy savings with rotating mass storage devices can be easily understood, it is quite difficult to design an effective and safe system.

In order to ensure the efficiency of the flywheel as an energy storage device, continuous losses through friction must be reduced to a minimum.

To do this, the housing of the flywheel must be maintained at low pressure or vacuum.

As a result, the housing is kept close to vacuum, so both heat generation and energy loss can be significantly reduced.

Therefore, there is a need to propose a suitable housing structure in which the interior is lower in pressure than the outside or can maintain a vacuum, such as the housing of the flywheel, in order to minimize energy losses such as friction.

2. Flywheel energy storage system

More specifically, the flywheel energy storage system (Flywheel energy storage system) as follows.

Flywheel energy storage system (Flywheel energy storage system) is a device for converting the electrical energy into a rotational energy form by rotating the rotor (rotator) using a motor (motor) to quickly rotate the supplied electrical energy.

In addition, a rotating body (or a rotor) having a rotating shaft generally uses a metal material such as steel at a low speed or uses a composite to form the rotating body.

In addition, a flywheel energy storage system (Flywheel energy storage system) is generally shown in Figure 1 flywheel management system (FMS), power conversion system (PCS, power conditioning system) for converting frequency and voltage, energy management And a power management system (PMS).

Then, before describing the present invention in earnest, the sealing housing form will be described.

In general, a mechanical device having a rotating body is most often a cylinder or disk type as shown in FIG. 2, which is formed by a circle having an upper surface and a lower surface facing it.

Similarly, the sealing housing of the flywheel energy storage system (Flywheel energy storage system) is also formed in the form of a cylinder or a flat cylinder (disk type) as shown in FIG.

In addition, since flywheel energy storage systems store energy by rotating a rotor in a housing, minimizing energy loss during rotation is a core technology.

In addition, energy loss mainly occurs between frictional losses and energy transfer (including electrical or thermal energy) by supporting members (including mechanical or electromagnetic bearings) such as bearings to support and maintain rotation of the rotor (rotor). Loss).

In addition, by utilizing a vacuum pump and a lip seal, the inside of the housing is kept in a vacuum state, thereby minimizing friction caused by fluid (air) that is rapidly lost as the speed of the rotor (rotor, bearing, etc.) increases. .

As shown in FIG. 3, a conventional housing type for a flywheel energy storage device is as follows.

In general, the cross-section of the sealing housing in the form of a cylinder is the same as the A type of FIG. 3, and is also manufactured in the B type of FIG.

In addition, the housing is subjected to external air pressure due to a vacuum inside or a pressure lower than the outside, and determines the thickness of the material and skin structure of the housing to sustain it.

Conventionally, as shown in FIG. 3, the pressure vessel is manufactured in the form of convex upper and lower portions, such as A type or B type, which is mainly used when the pressure vessel has a large pressure difference between the inside and the outside. .

In addition, as shown in FIG. 3, the structural analysis of applying air pressure to the outer surface of the two types, A type and B type, was performed. In the case of B type, the magnitude of the stress is much smaller than that of the A type. This is because the contact area is larger than the A type.

Accordingly, in the conventional hermetic housing, the B type having a convex shape toward the outside of the A type, in which the upper and lower surfaces thereof are generally flat, is very advantageous.

3. Hermetic housing proposed by the present invention

On the other hand, the present inventors have tried for many years as follows to develop a more advanced technology in the type B technology, the upper and lower parts of the hermetic housing is advantageously outwardly convex than the A flat type general flat type. .

As shown in FIG. 4, as a result of structural analysis of the C type as well as the B type, when the external pressure was higher than the inside, the C type housing showed a low stress and a uniform stress distribution.

Here, in FIG. 4, A type is a flat flat surface having a top portion and a bottom portion, and B type has a shape in which the top portion and the bottom portion are convex outward, and C type is the top portion and the bottom portion inward. It is concave.

Accordingly, the present invention proposes the use of a concave housing when the inside has a lower pressure than the outside.

In the present invention, the structural analysis using the finite element method (FEM) is as follows.

In this analysis, stainless steel used as the material of the general structure was used. The elastic modulus (Elastic modulus or Young's modulus) was 193 GPa and the density was 8,000 kg / m ³ .

For reference, in the present invention, the hermetic housing is divided into an inside and an outside, and a predetermined space is formed therein, and forms an interface between the inside and the outside.

3-1. First embodiment

As shown in FIG. 5, the sealed housing according to the first embodiment of the present invention and the sealed housing to be compared have a cylindrical shape. As shown in FIG. 5, the A type has a flat plate shape, and the B type is a top surface. And the lower surface portion is convex outward, and the C type has a shape in which the upper surface portion and the lower surface portion are concave inwardly.

Also, the hermetic housing and the comparison target hermetic housing proposed by the present invention were tested under the conditions of internal pressure (P _i) is a vacuum (0) and external pressure (P _o), the atmospheric pressure (1atm = 1013hPa).

However, the hermetic housing that suggested by the present invention satisfies the 1013hPa less than the range of more than 0Pa at a low condition is sufficient and the internal pressure (P _i) low condition than the atmospheric pressure than the internal pressure (P _i) is the external pressure (P _o) .

In more detail with respect to the vacuum region, in general, the type and application process of the vacuum pump according to the vacuum region can be divided as shown in Table 1 below.

For reference, the present invention can be more efficiently applied to the entire vacuum region up to Extremely High Vacuum including the Rough Vacuum region with an internal pressure of less than 1013 hPa lower than the external atmospheric pressure, and a flywheel for energy storage. ) Is generally driven in the medium vacuum region (1 Torr or less).

Vacuum area range Applied Process Vacuum pump model Low vacuum
(Rough Vacuum) Atmospheric pressure ~ 1 Torr
(1013hPa ~ 133 Pa) Vacuum adsorption transfer, automatic feeding of printer, vacuum enrichment reactor, powder filling, vacuum forming, vacuum packaging Dry rotary vane pump, lubricated rotary vane pump, water seal pump, steam ejector, refrigerant gas injection Medium vacuum
(Fine Vacuum) 1 Torr to 10 ^-3 Torr
(133 Pa ~ 0.13 Pa) Vacuum drying, degasser, vacuum impregnation, vacuum distillation, vacuum sintering Multi-stage rotary vane pump, multi-steam steam eject, roots pump, piston pump, diffusion pump High vacuum
(High Vacuum) 10 ^-3 Torr to 10 ^-7 Torr
(0.13 Pa ~ 1.3 × 10 ^-5 Pa) Vacuum coating, vacuum freeze drying, vacuum alloy, new material alloy Diffusion Pump, Turbo Molecular Pump, Adsorption Pump, Low Temperature Cooling Pump, Lift Pump Ultra high vacuum
Ultrahigh Vacuum 10 ^-7 Torr ~ 10 ^-10 Torr
(1.3 × 10 ^-5 Pa ~ 1.3 × 10 ^-8 Pa) Electron microscope, plasma generator, surface study, material analysis Turbomolecular pump, cryogenic pump, cryo pump, keter pump Ultra high vacuum
(Extremely High Vacuum) 10 ^-10 Torr or less
(1.3 × 10 ^-8 Pa or less) Nuclear Research, Particle Acceleration, Space Experiments, Physics Research Turbomolecular Pump, Low Temperature Cooling Pump, Ion Pump

In addition, in order to objectively compare the advantages of C type, B type and C type were analyzed with the same size and radius of curvature of the outer surface area under pressure.

On the other hand, the C type (concave) housing has a significant advantage that can be installed in the same size as the A type because there is no externally convex portion such as B type.

In addition, the C type (concave) is structurally more robust because of the relatively low stress level, unlike other types (A and B type), thereby making the thickness of the housing wall thinner, There is an advantage that the material of strength can be used.

Analysis using the finite element method (FEM) of the structure of the hermetic housing according to the first embodiment of the present invention is as follows.

The hermetic housing according to the first embodiment of the present invention and the conventional hermetic housing to be compared have a hollow cylinder shape, and FIG. 6 is a concave proposed by the present invention by enlarging the vicinity of the corner where the upper surface portion and the side portion meet. ), The conventional normal flat shape and the convex shape are shown.

Shapes and comparative shapes of the hermetic housing (housing) according to the first embodiment of the present invention is the case that the thickness of the interface surface of 7.5mm, the stress distribution data obtained as shown in FIG.

As shown in FIG. 7, the A type of the normal shape has a maximum stress (σ _max ) of 273.8 MPa, and it can be seen that the stress is severely concentrated in the vicinity of the edge of the upper or lower surface portion which meets the side portion. The convex type B has a maximum stress (σ _max ) of 189.0 MPa at the outer center and a higher stress at the outer center of the upper or lower surface, and concave inward. The type has the highest stress (σ _max ) at the inner center of 101.6MPa, which is about one third smaller than the highest stress of the A type, and about 1/2 smaller than the highest stress of the B type.

Shapes and comparative shapes of the hermetic housing (housing) according to the first embodiment of the present invention is 10.0mm thickness of the interface, the stress distribution data obtained as shown in FIG.

As shown in FIG. 8, the normal type A type has a maximum stress (σ _max ) of 183.6 MPa, and it can be seen that the stress is severely concentrated in the vicinity of the edge of the upper or lower surface portion that meets the side portion. The convex type B has a maximum stress (σ _max ) of 95.2 MPa at the outer center and a higher stress at the outer center of the upper or lower surface, and concave inward. The type has the highest stress (σ _max ) at 73.7 MPa in the inner center, which is about one third smaller than the highest stress of the A type, and about 2/3 smaller than the highest stress of the B type.

Shapes and comparative shapes of the hermetic housing (housing) according to the first embodiment of the present invention is 12.5mm thickness of the interface, the stress distribution data obtained as shown in FIG.

As shown in FIG. 9, in the A type of a normal shape, it can be seen that the maximum stress (σ _max ) is 130.3 MPa and the stress is severely concentrated in the vicinity of the edge of the upper or lower surface portion that meets the side portion. It can be seen that the convex type B has the highest stress (σ _max ) of 64.4 MPa and the stress increases to the outer center of the upper surface or the lower surface, and the C type of the concave shape is the highest. The stress (σ _max ) is 57.9 MPa, which is about 1/2 smaller than the highest stress of A type and about 4/5 smaller than the highest stress of B type.

Shapes and comparative shapes of the hermetic housing (housing) according to the first embodiment of the present invention, when the thickness of the interface is 15.0mm, the stress distribution data obtained as shown in FIG.

As shown in FIG. 10, in the A type of the normal shape, the highest stress σ _max is 86.7 MPa, and the stress is intensely concentrated near the edge of the upper or lower surface portion that meets the side portion. It can be seen that the convex type B has the highest stress (σ _max ) of 48.6 MPa and the stress increases to the outer center of the upper surface or the lower surface, and the C type of the concave shape is the highest. The stress (σ _max ) is 47.1 MPa, which is about 1/2 less than the maximum stress of A type, and 1.5 MPa is less than the maximum stress of B type.

Accordingly, the C type hermetic housing according to the first embodiment of the present invention has a lower stress magnitude and an even stress distribution than the A type or B type hermetic housing, which is structurally more robust.

Because of this, the thickness of the interface (upper surface, lower surface and side surface) can be made thinner than A type or B type, and a material of lower strength than A type or B type can be used.

In addition, the thinner the thickness of the interface is advantageous to the influence of the concave shape.

In addition, since the C type hermetic housing according to the first embodiment of the present invention has a high stress near the edge of the disc surface, only the edge may be locally supplemented.

In addition, since the structure is easy to reinforce the thickness in the vicinity of the face meets, it is very advantageous to manufacture.

In addition, since the C type hermetic housing according to the first embodiment of the present invention has no externally convex portion like the conventional B type, the C type hermetic housing can be sufficiently installed in a space of the same size and shape as the A type.

Therefore, not only to solve the spatial disadvantage of the conventional B type, but also superior to the spatial advantages of the conventional A type, it is possible to secure the free space.

3-2. Second embodiment

The hermetic housing according to the second embodiment of the present invention and the hermetically sealed housing to be compared have a hollow cylinder shape, and as shown in FIG. 11, A type is a flat disc shape in which a top surface and a bottom surface are generally flat, and B-1 type is a top surface. The upper and lower surfaces are convex to the outside, and the C-1 type has the upper and lower surfaces concave to the inside.

In addition, as shown in FIG. 11, the A type is a vertical hollow cylindrical shape having a side portion in general, and the B-1 type is a tire shape in which the side portion is convexed to the outer surface. It is shaped like a vial with concave sides.

Also, the hermetic housing and the comparison target hermetic housing proposed by the present invention were tested under the conditions of internal pressure (P _i) is a vacuum (0) and external pressure (P _o), the atmospheric pressure (1atm = 1013hPa).

However, the hermetic housing that suggested by the present invention satisfies the 1013hPa less than the range above 0hPa a low condition is sufficient and the internal pressure (P _i) low condition than the atmospheric pressure than the internal pressure (P _i) is the external pressure (P _o) .

In addition, to objectively compare the advantages of the C-1 type, the B-1 type and the C-1 type were analyzed with the same size and radius of curvature of the outer surface area under pressure.

On the other hand, the C-1 type (concave) housing has a significant advantage that can be installed in a space of the same size or smaller form as the A type because there is no externally convex portion, such as B-1 type.

In addition, the C-1 type (concave) is structurally stronger because of the low stress level, unlike other forms (A and B-1 type), thereby making the thickness of the housing side portion thinner, There is an advantage that a lower strength material can be used.

Analysis using the finite element method (FEM) of the structure of the hermetic housing according to the second embodiment of the present invention is as follows.

The hermetic housing according to the second embodiment of the present invention and the conventional hermetic housing to be compared are in the shape of a cylinder or a disk as shown in FIG. 2, and FIG. 12 is a concave whole of the interface proposed by the present invention. The convex state of the side part is shown in addition to the convex form of one form, the conventional normal flat form and the upper and lower surfaces.

Shapes and comparative shapes of the hermetic housing (housing) according to the second embodiment of the present invention is 10.0mm thickness of the interface, the stress distribution data obtained as shown in FIG.

As shown in FIG. 12, in the A type of a normal shape, it can be seen that the maximum stress (σ _max ) is 183.6 MPa, and the stress is severely concentrated in the vicinity of the edge of the upper surface or the lower surface that meets the side portion. The convex B-1 type has a maximum stress (σ _max ) of 95.0 MPa and the stress increases to the outer center of the upper or lower surface part, and the C- concave shape is concave inward. Type 1 has a maximum stress (σ _max ) of 73.6 MPa, which is about 2/5 less than the maximum stress of Type A, and about 2/3 less than the maximum stress of Type B.

Accordingly, the C-1 type hermetic housing according to the second embodiment of the present invention has a lower stress level and an even stress distribution than the A type or B-1 type hermetic housing, and thus is more structurally robust.

Because of this, the thickness of the interface (upper surface, lower surface and side portion) can be made thinner than A type or B-1 type, and materials of lower strength than A type or B-1 type can be used.

In addition, the C-1 type sealed housing according to the second embodiment of the present invention has a high stress in the vicinity of the edge of the upper surface or the lower surface, so that only the vicinity of the edge may locally compensate for the thickness.

In addition, since the structure is easy to reinforce the thickness in the vicinity of the face meets, it is very advantageous to manufacture.

In addition, since the C-1 type hermetic housing according to the second embodiment of the present invention does not have an externally convex portion like the conventional B-1 type, the C-1 type hermetic housing is sufficiently installed in a space of the same size and shape as the A type. It is possible.

Therefore, not only to solve the spatial disadvantage of the conventional B-1 type, but also superior to the spatial advantages of the conventional A type can also secure a free space.

3-3. Third embodiment

The sealed housing according to the third embodiment of the present invention and the sealed housing to be compared have a hollow hexahedron shape, and as shown in FIG. 13, A 'type is a general flat flat form of a hexahedron having a square top and bottom sides. , B 'type is a convex form (convex) to the outside of the cube, the top and bottom and the rectangle is square, C' type is concave (concave) inside the cube.

Also, the hermetic housing and the comparison target hermetic housing proposed by the present invention were tested under the conditions of internal pressure (P _i) is a vacuum (0) and external pressure (P _o), the atmospheric pressure (1atm = 1013hPa).

However, the hermetic housing that suggested by the present invention satisfies the 1013hPa less than the range above 0hPa a low condition is sufficient and the internal pressure (P _i) low condition than the atmospheric pressure than the internal pressure (P _i) is the external pressure (P _o) .

In addition, in order to objectively compare the advantages of the C 'type, the analysis of the A' type, B 'type and C' type with the thickness of the interface 10mm and the length of one side was 1340mm the same.

On the other hand, the C 'type (concave) housing has a significant advantage that can be installed in a space of the same size or smaller form as the A' type because there is no externally convex portion, such as B 'type.

In addition, the C 'type (concave) is structurally more robust because of the lower stress level, unlike other types (A' and B 'type), thereby making the thickness of the housing (housing) thinner, There is an advantage that the material of strength can be used.

Analysis using the finite element method (FEM) of the structure of the hermetic housing according to the third embodiment of the present invention is as follows.

The hermetic housing according to the third embodiment of the present invention and the conventional hermetic housing to be compared have a hexahedral shape, and FIG. 13 is a shape in which the entire interface of the hexagonal surface proposed by the present invention is concave. It has a flat surface and convex shape of the whole surface.

Shapes and comparative shapes of the hermetic housing (housing) according to the third embodiment of the present invention, when the thickness of the interface is 10.0mm, the stress distribution data was obtained as shown in FIG.

As shown in FIG. 14, the A 'type of the normal shape has a maximum stress (σ _max ) of 445.7 MPa and it can be seen that the stress is severely concentrated near the edge where the face meets the face, and convex to the outside. The convex type B 'type has the highest stress (σ _max ) of 389.3 MPa and the stress is concentrated inside the edge where the face meets the surface. The C' type of concave shape is It can be seen that the maximum stress (σ _max ) is 271.6MPa and the stress increases in the bending portion of the edge where the face meets.

15 to 17 are views for comparing a hermetic housing according to a third embodiment of the present invention and a conventional hermetic housing to be compared, and FIG. 15 is an enlarged cross-sectional view of an edge near a face where the face meets the present invention. The concave shape of the proposed cube (C 'type), Figure 16 is a convex shape (B' type) of the cube, Figure 17 is a normal flat shape (A 'type) of the cube Is showing.

Accordingly, the C 'type hermetic housing according to the third embodiment of the present invention has a lower stress level and an even distribution of stress than the A' type or B 'type hermetic housing, which is structurally more robust.

Because of this, the thickness of the interface (upper surface, lower surface and side) can be made thinner than A 'type or B' type, and materials of lower strength than A 'type or B' type can be used.

In addition, the C 'type closed housing (housing) according to the third embodiment of the present invention has a high stress in the vicinity of the edge of each of the upper surface portion, the lower surface portion and the side portion, so that only the vicinity of the edge can locally compensate for the thickness. However, it is very advantageous to manufacture because it is near the edge of the easy-to-reinforced structure where the face meets.

In addition, the C 'type sealed housing (housing) according to the third embodiment of the present invention can be sufficiently installed in a space of the same size and shape as the A' type since there is no externally convex portion like the conventional B 'type. It not only solves the spatial disadvantages of the conventional B 'type, but also is superior to the spatial advantages of the conventional A' type, thereby ensuring the free space.

As such, the enclosed housing proposed by the present invention is extended to be applied to a shape of a cylinder or a polyhedron including a hexahedron, and even a shape close to a sphere, such as a golf ball, which is divided into an interior and an exterior, and a predetermined space is provided in the interior. And a predetermined curvature is formed to form the inner and outer boundaries, the pressure inside the lower than the external pressure, and the interface enters concave inward.

4. Conclusion

An enclosed housing according to an embodiment of the present invention is a housing having a sealed inner space.

An upper surface of a predetermined thickness,

A lower surface portion having a predetermined thickness spaced apart from the upper surface portion by a predetermined distance, and

Wherein the circumference of the upper surface portion and the circumference of the lower surface portion is made to include a side portion of a predetermined thickness forming a surface,

The inner space is a space formed around the upper surface portion, the lower surface portion and the side portion,

When the pressure of the inner space is lower than the pressure outside the housing, the upper and lower parts to lower the stress and to uniform the stress distribution than the case where each of the upper and lower surfaces are convex toward the exterior of the housing. Each lower surface portion is formed to be concave into the inner space at a predetermined curvature.

Here, the upper surface portion and the lower surface portion is the same size, the side portion is perpendicular to the upper surface portion and the lower surface portion.

In addition, the sealed housing according to another embodiment of the present invention (housing) of the upper and lower portions of each of the disk-shaped and the side portion is a cylinder (cylinder) shape.

In addition, the hermetic housing according to another embodiment of the present invention (housing) is a top plate and a lower portion of each of the rectangular plate shape, the side portion is a plate shape connecting the edge of the upper surface portion and the edge of the lower surface portion.

In addition, the hermetic housing according to another embodiment of the present invention (housing) is a plate-shaped each of the upper surface and the lower surface is a polygonal plate shape, the side portion connecting the edge of the upper surface portion and the edge of the lower surface portion.

In addition, in the hermetic housing proposed by the present invention, the side portion is concave into the predetermined space to form a predetermined curvature.

In addition, the hermetic housing (housing) proposed in the present invention is provided with a rotor having a rotating shaft that rotates by the drive of the motor in the inner space, the rotating shaft passes through the center of the upper and lower surfaces, The rotating body stores the rotation force generated by the driving of the motor.

Here, the rotating body corresponds to a rotor of a flywheel energy storage system as shown in FIG. 1, and the supporting member includes a mechanical or electromagnetic bearing.

Therefore, the sealed housing proposed in the present invention can expect the following effects.

The hermetic housing (C, C-1, C 'type) of the present invention is lower than the conventional hermetic housing (A, A', B, B-1, or B 'type) has a lower stress magnitude and even distribution of stresses There is a solid advantage.

For reference, A, A 'type is called A type, B, B-1, or B' type is called B type, and C, C-1 or C 'type is called C type.

In addition, there is an advantage that the thickness of the interface can be made thinner than conventional and that a material having a lower strength than the conventional one can be used.

In addition, since the hermetic housing of the present invention has a high stress in the vicinity of the rim, not only can the thickness be locally supplemented in the vicinity of the rim, but also has the advantage of being easy to reinforce and easy to manufacture.

In addition, the hermetic housing of the present invention can be sufficiently installed in a space of the same size and shape as a conventional flat housing (A type) than a conventional convex housing (B type).

In addition, not only to solve the spatial disadvantage of the conventional convex housing (B type), but also superior to the spatial advantages of the conventional flat housing (A type), there is an advantage that can secure a free space.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains various modifications, changes, and substitutions without departing from the essential characteristics of the present invention. will be.

Accordingly, the embodiments disclosed in the present invention and the accompanying drawings are not intended to limit the technical spirit of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by the embodiments and the accompanying drawings. .

The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

Claims (5)

In a housing having a closed inner space,
An upper surface of a predetermined thickness,
A lower surface portion having a predetermined thickness spaced apart from the upper surface portion by a predetermined distance, and
Wherein the circumference of the upper surface portion and the circumference of the lower surface portion is made to include a side portion of a predetermined thickness forming a surface,
The inner space is a space formed around the upper surface portion, the lower surface portion and the side portion,
When the pressure of the inner space is lower than the pressure outside the housing, the upper and lower parts to lower the stress and to uniform the stress distribution than the case where each of the upper and lower surfaces are convex toward the exterior of the housing. A closed housing characterized in that each of the lower surface portion is formed to be concave (concave) into the inner space at a predetermined curvature. The method of claim 1,
Each of the upper and lower surfaces is disc-shaped,
The side surface portion is sealed housing, characterized in that the cylinder. The method of claim 1,
Each of the upper and lower surface portions is a rectangular plate shape,
The side surface portion is a sealed housing, characterized in that the plate-shaped connecting the edge of the upper surface portion and the edge of the lower surface portion. The method of claim 1,
Each of the upper and lower surfaces has a polygonal plate shape,
The sealed housing, characterized in that the side portion is a plate-shaped connecting the edge of the upper surface portion and the edge of the lower surface portion. The method of claim 1,
The inner space is provided with a rotor having a rotating shaft that rotates by driving of the motor, the rotating shaft passes through the center of the upper and lower surfaces and the rotating body stores the rotational force generated by the driving of the motor Sealed housing, characterized in that.

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