阅读说明：本技术 电力机车用超低温齿轮箱测试装置 (Ultra-low temperature gearbox testing device for electric locomotive ) 是由 丁杰 于 2021-10-22 设计创作，主要内容包括：本发明公开了电力机车用超低温齿轮箱测试装置,包括：低温测试箱、测试托板、液氮降温舱和震动击锤机构,低温测试箱的顶面和侧面分别设有密封顶盖和侧入料盖板,低温测试箱的内部固定安装有制冷盘管组件,液氮降温舱位于低温测试箱的一侧并与低温测试箱的内腔相连通,震动击锤机构固定安装于低温测试箱的内部。本发明中,通过设置双重制冷降温结构,利用制冷盘管组件进行低温测试箱内部低温环境的建立,并通过液氮降温舱释放液氮通过曝散进入低温测试箱内部的对低温测试箱的内部测试环境进行急剧降温,从而模拟急剧低温下球墨铸铁齿轮箱韧脆转变性质,完全反应球墨铸铁齿轮箱的结构性质。(The invention discloses an ultralow temperature gearbox testing device for an electric locomotive, which comprises: the liquid nitrogen cooling cabin is located on one side of the low-temperature testing box and communicated with an inner cavity of the low-temperature testing box, and the vibration hammer mechanism is fixedly installed inside the low-temperature testing box. According to the invention, a double refrigeration cooling structure is arranged, a refrigeration coil assembly is utilized to establish a low-temperature environment in the low-temperature test box, and liquid nitrogen released by the liquid nitrogen cooling cabin enters the low-temperature test box through aeration and dispersion to rapidly cool the internal test environment of the low-temperature test box, so that the ductile-brittle transition property of the nodular cast iron gearbox at a rapid low temperature is simulated, and the structural property of the nodular cast iron gearbox is completely reflected.)

1. Ultra-low temperature gear box testing arrangement for electric locomotive, its characterized in that includes: the device comprises a low-temperature test box (100), a test supporting plate (200), a liquid nitrogen cooling cabin (300) and a vibration hammer mechanism (400), wherein the top surface and the side surface of the low-temperature test box (100) are respectively provided with a sealing top cover (110) and a side feeding cover plate (120), a refrigeration coil assembly (150) is fixedly installed inside the low-temperature test box (100), the liquid nitrogen cooling cabin (300) is positioned on one side of the low-temperature test box (100) and communicated with an inner cavity of the low-temperature test box (100), and the vibration hammer mechanism (400) is fixedly installed inside the low-temperature test box (100);

a compression storage tank (310) is arranged inside the liquid nitrogen cooling cabin (300), a through groove communicated with the inner cavity of the low-temperature test box (100) is formed in one side of the liquid nitrogen cooling cabin (300), an aeration fan (320) is embedded and mounted in the inner side of the barrel groove, and the output end of the compression storage tank (310) is fixedly connected with a release valve group (311) located on one side of the aeration fan (320);

vibrations hammer mechanism (400) including be fixed in the inside fixed support board (410) of low temperature test case (100) and fixed mounting in fixed vibration drive assembly (420) and the motion hammer (430) of support board (410) bottom surface, motion hammer (430) fixed mounting is in the output of vibration drive assembly (420), vibration drive assembly (420) are including shock attenuation base plate (421), high frequency vibrations machine (422) and vibrations linkage (423) are fixed in the bottom surface of shock attenuation base plate (421) and with the top surface fixed connection of motion hammer (430).

2. The ultra-low temperature gearbox testing device for the electric locomotive according to the claim 1, characterized in that the refrigeration coil assembly (150) comprises an upper coil group (151) and a lower refrigeration coil (152), the upper coil group (151) and the lower refrigeration coil (152) are respectively located on the upper surface and the lower surface of the inner cavity of the low temperature test box (100), and refrigeration equipment is fixedly connected to the ends of the upper coil group (151) and the lower refrigeration coil (152).

3. The ultra-low temperature gearbox testing device for the electric locomotive according to the claim 1, characterized in that a damping slide rail (210) is embedded and mounted on the top surface of the testing support plate (200), a motion clamping seat (220) is slidably mounted on the top surface of the damping slide rail (210), the testing support plate (200) is slidably mounted inside the low temperature testing box (100), and a testing clamping plate (230) is fixedly mounted on the top surface of the motion clamping seat (220).

4. The ultra-low temperature gearbox testing device for the electric locomotive according to claim 3, characterized in that the bottom surface of the motion clamping seat (220) is provided with a damping slider (221) and is slidably mounted on the surface of the damping slide rail (210) through the damping slider (221), the damping slider (221) is in a damping rubber block structure, the number of the motion clamping seats (220) is four and is divided into two groups, and each group of the test clamping plates (230) is symmetrically arranged on the surface of the same damping slide rail (210).

5. The ultra-low temperature gearbox testing device for the electric locomotive according to the claim 3, characterized in that a vibration sensor is embedded in the surface of the testing clamping plate (230), and the output end of the vibration sensor is electrically connected with a vibration frequency spectrograph for displaying vibration frequency images.

6. The ultra-low temperature gearbox testing device for the electric locomotive according to the claim 1 is characterized in that a vacuum heat insulation layer (111) is arranged inside the low temperature testing box (100), a sealing rubber ring (112) is arranged on the bottom surface of the sealing top cover (110), the periphery of the sealing rubber ring (112) is in interference fit with the inner side of the low temperature testing box (100), the inner wall of the low temperature testing box (100) is provided with a polyester foam layer (130) and a heat insulation cotton plate layer (140), and the heat insulation cotton plate layer (140) is made of asbestos heat insulation plate materials.

7. The ultra-low temperature gearbox testing device for the electric locomotive according to claim 1, wherein the relief valve set (311) is an electromagnetic control valve structure, the inside of the compression storage tank (310) is filled with liquid nitrogen, and the internal pressure of the compression storage tank (310) is 1.5 MPa.

8. The ultra-low temperature gearbox testing device for the electric locomotive according to claim 1, wherein the top surface of the damping base plate (421) is fixedly provided with a damping spring connected with the bottom surface of the fixed supporting plate (410), the high frequency vibrator (422) is of a crankshaft vibrator structure, the vibration linkage member (423) is of a parallelogram structure, four sides of the vibration linkage member (423) are hinged with each other, and the bottom surface of the vibration linkage member (423) is fixedly connected with the top surface of the moving hammer (430).

Technical Field

The invention relates to the technical field of low-temperature testing, in particular to an ultralow-temperature gearbox testing device for an electric locomotive.

Background

The toughness of ductile iron generally decreases with a decrease in temperature, and when the temperature is lower than a certain temperature, brittle fracture, so-called ductile-brittle transition, occurs due to a sharp decrease in toughness. In recent years, the rail transit industry in China is rapidly developed, the electric locomotive is wide in operation region, the latitude span is large, the temperature in cold regions in winter can reach below-40 ℃, and the requirement on the low-temperature impact toughness of the nodular cast iron gear box for the electric locomotive is higher and higher based on the consideration of the operation speed and the safety of the locomotive. The TJ/JW065-2015 temporary technical conditions of the nodular iron gear box of the AC transmission locomotive of China railway general company provides that the nodular iron gear box not only needs to have the mechanical property of QT500-7A specified by the national standard GB/T1348-2009, but also needs to have higher elongation and low-temperature impact toughness, namely: the elongation A is more than or equal to 8 percent, the average value of the impact energy at minus 40 ℃ is more than or equal to 4J, and the single value is more than or equal to 3J. The conventional QT500-7A nodular cast iron material cannot meet the requirement.

The obtained casting and the attached casting test block thereof have low-temperature impact toughness at-40 ℃ generally reaching more than 12J and higher elongation rate of more than 18 percent, but the strength index is far away from QT500-7A, only the tensile strength Rm is more than or equal to 380MPa, the yield Rp0.2 is more than or equal to 240MPa, and after spheroidizing inoculation treatment, high-temperature graphitization annealing treatment is also needed. The invention patent application of china 201310114040.4 discloses a low-temperature high-toughness nodular cast iron bearing seat and a manufacturing method thereof, which purportedly can improve the low-temperature impact toughness of nodular cast iron castings.

A series of low-temperature tests are required after the production of the ultralow-temperature gearbox is finished, the existing ultralow-temperature test equipment mainly adopts circulating compression refrigeration equipment to circularly cool a test area to below-40 ℃ to measure the ductile-brittle transition of the equipment, and the test has certain defects because the efficiency of the compression refrigeration equipment is limited to below-40 ℃ and the ductile-brittle transition property of the nodular cast iron gearbox at a sharp low temperature cannot be continuously and quickly cooled and the cooling effect is slow.

In view of the above, the present invention provides an ultra-low temperature gearbox testing device for an electric locomotive, which is improved to solve the problems that the conventional testing device cannot simulate the ductile-brittle transition at the rapid low temperature and the testing error, and aims to achieve the purposes of solving the problems and improving the practical value through the technology.

Disclosure of Invention

The present invention is directed to solving one of the technical problems of the prior art or the related art.

Therefore, the technical scheme adopted by the invention is as follows: electric locomotive is with ultra-low temperature gear box testing arrangement includes: the device comprises a low-temperature test box, a test supporting plate, a liquid nitrogen cooling cabin and a vibration hammer mechanism, wherein the top surface and the side surface of the low-temperature test box are respectively provided with a sealing top cover and a side feeding cover plate; a compression storage tank is arranged in the liquid nitrogen cooling cabin, a through groove communicated with the inner cavity of the low-temperature test box is formed in one side of the liquid nitrogen cooling cabin, an aeration fan is embedded and mounted in the inner side of the barrel groove, and a release valve group positioned on one side of the aeration fan is fixedly connected to the output end of the compression storage tank; the vibration hammer mechanism comprises a fixed support plate fixed inside the low-temperature test box and a vibration driving assembly and a motion hammer which are fixedly installed on the bottom surface of the fixed support plate, the motion hammer is fixedly installed at the output end of the vibration driving assembly, the vibration driving assembly comprises a damping substrate, a high-frequency vibrator and a vibration linkage piece, and the high-frequency vibrator and the vibration linkage piece are fixed on the bottom surface of the damping substrate and fixedly connected with the top surface of the motion hammer.

The present invention in a preferred example may be further configured to: the refrigeration coil assembly comprises an upper coil pipe group and a lower refrigeration coil, the upper coil pipe group and the lower refrigeration coil are respectively positioned on the upper surface and the lower surface of the inner cavity of the low-temperature test box, and refrigeration equipment is fixedly connected to the end parts of the upper coil pipe group and the lower refrigeration coil.

Through adopting above-mentioned technical scheme, utilize the refrigeration coil subassembly to carry out the inside low temperature environment's of low temperature test box establishment, violent vaporization when keeping the inside low temperature environment of low temperature test box and avoiding liquid nitrogen release influences cooling effect, flow through the inside circulation of compression refrigeration plant refrigerant refrigeration coil subassembly and carry out repeated heat absorption cooling to the inside air of low temperature test box.

The present invention in a preferred example may be further configured to: the testing device comprises a testing support plate, a damping slide rail, a motion clamping seat, a testing clamp plate and a testing clamp plate, wherein the damping slide rail is embedded in the top surface of the testing support plate, the motion clamping seat is slidably mounted on the top surface of the damping slide rail, the testing support plate is slidably mounted inside a low-temperature testing box, and the testing clamp plate is fixedly mounted on the top surface of the motion clamping seat.

Furthermore, the bottom surface of the motion clamping seat is provided with damping sliders and is slidably mounted on the surface of the damping slide rail through the damping sliders, the damping sliders are of a damping rubber block structure, the number of the motion clamping seats is four and is equally divided into two groups, and each group of test clamping plates are symmetrically arranged on the surface of the same damping slide rail.

Through adopting above-mentioned technical scheme, the gear box that will await measuring is placed in the motion cassette and the test splint of damping slide rail surface and slip both sides and is carried out the centre gripping to the gear box fixed, push into the inside of low temperature test box, adopt the airtight test box structure of pull formula, utilize the test layer board to carry out the installation centre gripping of gear box work piece, adopt pull formula to get into the structure and avoid the manual contact with the cooling gear box of operating personnel, and carry out the centre gripping through surperficial damping sliding assembly to the work piece that awaits measuring fixed, simple structure simple operation is convenient, and avoid personnel's low temperature frostbite to improve this test equipment's security.

The present invention in a preferred example may be further configured to: the inside of low temperature test box is equipped with vacuum insulation layer, the bottom surface of sealing top cap is equipped with sealed rubber ring, the inboard interference fit of the periphery and the low temperature test box of sealed rubber ring, the inner wall of low temperature test box is equipped with polyester foam layer and thermal-insulated cotton board layer, the thermal-insulated cotton board layer is asbestos heat insulating board material component.

Through adopting above-mentioned technical scheme, adopt vacuum insulation layer, polyester foam layer and thermal-insulated cotton layer to carry out the thermal-insulated heat preservation of seal cap and low temperature test box respectively, avoid external high temperature environment to the microthermal interference in low temperature test box in the test, thereby keep the inside low temperature environment simulation that lasts of low temperature test box to guarantee long-time.

The present invention in a preferred example may be further configured to: the release valve group is of an electromagnetic control valve structure, liquid nitrogen is filled in the compression storage tank, and the internal pressure of the compression storage tank is 1.5 MPa.

Through adopting above-mentioned technical scheme, store up the nitrogen technique through adopting the compression, the inside liquid nitrogen of compression storage tank can expose to the sun fast and scatter the blowout and carry out rapid vaporization cooling to the internal environment of low temperature test box after release valves opens, improves cooling efficiency.

The present invention in a preferred example may be further configured to: the damping base plate's top surface is fixed to be equipped with the damping spring who is connected with the fixed backup pad bottom surface, the high-frequency vibration machine is bent axle vibrations machine structure, the vibrations linkage is parallelogram structure, and the four sides of vibrations linkage are articulated each other and are connected, the bottom surface of vibrations linkage and the top surface fixed connection of motion drive hammer, the surface embedding of test splint installs the vibrations sensor, the output electric connection of vibrations sensor has the vibrations frequency spectrograph that is used for showing the vibration frequency image.

By adopting the technical scheme, the ductile-brittle transition property of the graphite cast iron gear box is changed by adopting a vibration hammer and vibration frequency spectrum analysis, and the ductile-brittle transition property is accurately analyzed by respectively reflecting the physicochemical property transition of the gear box through the vibration frequency spectrum change generated by striking the ductile-brittle transition surface of the graphite cast iron gear box at the same hammer frequency under normal temperature and ultralow temperature environments.

The beneficial effects obtained by the invention are as follows:

1. according to the invention, a double refrigeration cooling structure is arranged, a refrigeration coil assembly is utilized to establish a low-temperature environment in the low-temperature test box, and liquid nitrogen released by the liquid nitrogen cooling cabin enters the low-temperature test box through aeration and dispersion to rapidly cool the internal test environment of the low-temperature test box, so that the ductile-brittle transition property of the nodular cast iron gearbox at a rapid low temperature is simulated, and the structural property of the nodular cast iron gearbox is completely reflected.

2. According to the invention, the drawing type closed test box structure is adopted, the test supporting plate is utilized to install and clamp the gear box workpiece, the drawing type entering structure is adopted to avoid the manual contact of an operator with the cooling gear box, the workpiece to be tested is clamped and fixed through the surface damping sliding assembly, the structure is simple, the operation is convenient and fast, the low-temperature frostbite of the operator is avoided, and the safety of the test equipment is improved.

3. In the invention, the ductile-brittle transition property of the cast iron gearbox is changed by adopting a vibration hammer and vibration spectrum analysis, and the physical and chemical property transition of the gearbox is reflected by the vibration spectrum change generated by striking the ductile-brittle transition surface of the cast iron gearbox at the same hammer frequency in normal temperature and ultralow temperature environments respectively, so that the ductile-brittle transition property is accurately analyzed, and the test accuracy is improved.

Drawings

FIG. 1 is a schematic overall structure diagram of one embodiment of the present invention;

FIG. 2 is a schematic view of the internal structure of a low temperature test chamber according to an embodiment of the present invention;

FIG. 3 is a schematic view of a surface structure of a test pallet according to one embodiment of the present invention;

FIG. 4 is a schematic view of a refrigeration coil assembly according to one embodiment of the present invention;

FIG. 5 is a schematic cross-sectional view of a low temperature test chamber according to an embodiment of the present invention;

FIG. 6 is a schematic view of the internal structure of a liquid nitrogen cooling cabin according to an embodiment of the present invention;

fig. 7 is a schematic structural diagram of a vibration driving assembly according to an embodiment of the present invention.

Reference numerals:

100. a low temperature test chamber; 110. sealing the top cover; 120. a side feeding cover plate; 130. a polyester foam layer; 140. a heat insulating cotton board layer; 150. a refrigeration coil assembly; 111. a vacuum heat insulation layer; 112. sealing the rubber ring; 151. an upper coil pipe group; 152. a lower refrigeration coil;

200. testing the supporting plate; 210. damping the slide rail; 220. a motion cassette; 230. testing the clamping plate; 221. a damping slider;

300. a liquid nitrogen cooling cabin; 310. compressing the storage tank; 320. an aeration fan; 311. a release valve block;

400. a vibration hammer mechanism; 410. fixing a support plate; 420. a vibration driving assembly; 430. moving the hammer; 421. a shock-absorbing base plate; 422. a high-frequency vibrator; 423. the linkage is vibrated.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings in conjunction with the following detailed description. It should be noted that the embodiments of the present invention and features of the embodiments may be combined with each other without conflict.

It is to be understood that this description is made only by way of example and not as a limitation on the scope of the invention.

The ultra-low temperature gearbox testing device for the electric locomotive provided by some embodiments of the invention is described in the following with reference to the attached drawings.

As shown in fig. 1 to 7, the present invention provides an ultra-low temperature gearbox testing apparatus for an electric locomotive, comprising: the low-temperature testing device comprises a low-temperature testing box 100, a testing supporting plate 200, a liquid nitrogen cooling cabin 300 and a vibration hammer mechanism 400, wherein the top surface and the side surface of the low-temperature testing box 100 are respectively provided with a sealing top cover 110 and a side feeding cover plate 120, a refrigeration coil assembly 150 is fixedly arranged inside the low-temperature testing box 100, the liquid nitrogen cooling cabin 300 is positioned at one side of the low-temperature testing box 100 and communicated with the inner cavity of the low-temperature testing box 100, and the vibration hammer mechanism 400 is fixedly arranged inside the low-temperature testing box 100; a compression storage tank 310 is arranged in the liquid nitrogen cooling cabin 300, a through groove communicated with the inner cavity of the low-temperature test box 100 is formed in one side of the liquid nitrogen cooling cabin 300, an aeration fan 320 is embedded in the inner side of the barrel groove, and the output end of the compression storage tank 310 is fixedly connected with a release valve set 311 positioned on one side of the aeration fan 320; the vibration hammer mechanism 400 includes a fixed support plate 410 fixed inside the low temperature test chamber 100, and a vibration driving assembly 420 and a moving hammer 430 fixedly installed on a bottom surface of the fixed support plate 410, the moving hammer 430 is fixedly installed on an output end of the vibration driving assembly 420, the vibration driving assembly 420 includes a vibration-damping base plate 421, a high-frequency vibrator 422 and a vibration link 423, and the high-frequency vibrator 422 and the vibration link 423 are fixed on a bottom surface of the vibration-damping base plate 421 and are fixedly connected with a top surface of the moving hammer 430.

The present invention in a preferred example may be further configured to: the refrigeration coil assembly 150 includes an upper coil group 151 and a lower refrigeration coil 152, the upper coil group 151 and the lower refrigeration coil 152 are respectively located on the upper and lower surfaces of the inner cavity of the low-temperature test box 100, and the ends of the upper coil group 151 and the lower refrigeration coil 152 are both fixedly connected with refrigeration equipment.

Specifically, utilize refrigeration coil subassembly 150 to carry out the inside low temperature environment's of low temperature test box 100 establishment, violent vaporization when keeping the inside low temperature environment of low temperature test box 100 and avoiding liquid nitrogen release influences cooling effect, flow through the inside circulation of compression refrigeration plant refrigerant at refrigeration coil subassembly 150 and carry out repeated heat absorption cooling to the inside air of low temperature test box 100.

In this embodiment, a damping slide rail 210 is embedded in the top surface of the test tray 200, a motion clamping seat 220 is slidably mounted on the top surface of the damping slide rail 210, the test tray 200 is slidably mounted inside the low-temperature test chamber 100, and a test clamping plate 230 is fixedly mounted on the top surface of the motion clamping seat 220.

Further, the bottom surface of the motion clamping seat 220 is provided with a damping slider 221 and is slidably mounted on the surface of the damping slide rail 210 through the damping slider 221, the damping slider 221 is of a damping rubber block structure, the number of the motion clamping seats 220 is four and is equally divided into two groups, and each group of the test clamping plates 230 is symmetrically arranged on the surface of the same damping slide rail 210.

Concretely, the gear box that will await measuring is placed in motion cassette 220 and the test splint 230 of damping slide rail 210 surface and slip both sides and is carried out the centre gripping fixedly to the gear box, push the inside of low temperature test box 100, adopt the airtight test box structure of pull formula, utilize test layer board 200 to carry out the installation centre gripping of gear box work piece, adopt the pull formula to get into the structure and avoid the manual contact with the cooling gear box of operating personnel, and it is fixed to carry out the centre gripping to the work piece that awaits measuring through surperficial damping sliding assembly, simple structure simple operation is convenient, and avoid personnel's low temperature frostbite to improve this test equipment's security.

In this embodiment, a vacuum insulation layer 111 is disposed inside the low-temperature testing box 100, a sealing rubber ring 112 is disposed on the bottom surface of the sealing top cover 110, the outer periphery of the sealing rubber ring 112 is in interference fit with the inner side of the low-temperature testing box 100, a polyester foam layer 130 and an insulation cotton board layer 140 are disposed on the inner wall of the low-temperature testing box 100, and the insulation cotton board layer 140 is made of an asbestos insulation board material.

Specifically, adopt vacuum thermal-insulated layer 111, polyester foam layer 130 and thermal-insulated cotton layer 140 respectively to carry out the thermal-insulated heat preservation of seal cover 110 and low temperature test box 100, avoid external high temperature environment to the inside microthermal interference of low temperature test box 100 in the test, thereby keep the inside low temperature that lasts of low temperature test box 100 to guarantee long-time low temperature environment simulation.

In this embodiment, the release valve set 311 is an electromagnetic control valve structure, liquid nitrogen is filled in the compression storage tank 310, the internal pressure of the compression storage tank 310 is 1.5MPa, the refrigeration coil assembly 150 is used to establish the low-temperature environment inside the low-temperature test box 100 by setting a dual refrigeration cooling structure, and the liquid nitrogen released by the liquid nitrogen cooling cabin 300 enters the low-temperature test box 100 through aeration to rapidly cool the internal test environment of the low-temperature test box 100, so that the ductile-brittle transition property of the nodular cast iron gearbox at a rapid low temperature is simulated, and the structural property of the nodular cast iron gearbox is completely reflected.

Specifically, by adopting the compressed nitrogen storage technology, after the release valve set 311 is opened, the liquid nitrogen inside the compressed storage tank 310 can be quickly exposed and sprayed out to quickly vaporize and cool the internal environment of the low-temperature test box 100, so that the cooling efficiency is improved.

In this embodiment, a damping spring connected to the bottom surface of the fixed supporting plate 410 is fixedly disposed on the top surface of the damping substrate 421, the high-frequency vibrator 422 is a crankshaft vibrator structure, the vibration link 423 is a parallelogram structure, four sides of the vibration link 423 are hinged to each other, the bottom surface of the vibration link 423 is fixedly connected to the top surface of the moving hammer 430, a vibration sensor is embedded in the surface of the testing clamp plate 230, and an output end of the vibration sensor is electrically connected to a vibration spectrometer for displaying a vibration frequency image.

Specifically, the ductile-brittle transition property of the cast iron gear box is changed by adopting a vibration hammer and vibration spectrum analysis, and the ductile-brittle transition property is accurately analyzed by respectively reflecting the physicochemical property transition of the gear box through the vibration spectrum change generated by striking the ductile-brittle transition surface of the cast iron gear box at the same hammer frequency under normal temperature and ultralow temperature environments.

In the present invention, the term "plurality" means two or more unless explicitly defined otherwise. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. The terms "mounted," "connected," "fixed," and the like are used broadly and encompass, for example, a fixed connection, a removable connection, or an integral connection, and a connection may be a direct connection or an indirect connection via intermediate media. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

It will be understood that when an element is referred to as being "mounted to," "secured to" or "disposed on" another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may also be present. The terms "vertical," "horizontal," "upper," "lower," "left," "right," and the like as used herein are for illustrative purposes only and do not denote a unique embodiment.

In the description herein, the description of the terms "one embodiment," "some embodiments," "specific embodiments," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents.