Abstract:
The present invention relates to a level gauge, and more particularly, to a level gauge provided on a device such as an engine or transmission of a vehicle to discharge aft from the device and prevent a foreign substance from being introduced therein. In addition, the level gauge and an oil net can be integrated into a single module, to thereby save costs.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a U.S. National Stage Application of International Application No. PCT/KR2010/009400, filed on Dec. 28, 2010 and published in Korean as WO 2012/091190 A1 on Jul. 5, 2012. The disclosures of the above applications are incorporated herein by reference. 
     FIELD OF THE INVENTION 
     The present invention relates to a level gauge. More particularly, the present invention relates to a level gauge that is disposed on a mechanical device such as an engine or a transmission of a vehicle so that air inside the engine is discharged, introduction of foreign substances into the engine is prevented, and the level gauge and an oil injection port can be integrated into a single module, thereby reducing the manufacturing costs. 
     BACKGROUND OF THE INVENTION 
     In general, a mechanical device such as an engine or a transmission of a machine (hereinafter, referred to as “vehicle”) such as an automobile or a construction machine requires that oil should be supplied to a sliding part in order to perform a smooth operation of an operating part and maintain the lifespan of the operating part for a long period of time. 
     Viscosity and lubrication properties of the oil supplied to the engine of a vehicle are deteriorated over time due to oxidation by the contact between the oil and the air, abrasion of the sliding part, or the mixture of the oil and impurities introduced into the engine from the outside. Thus, a driver or an operator must check the state of the oil periodically to exchange the oil at the appropriate times. 
       FIG. 1  is a view showing the installation state of a conventional level gauge in accordance with the prior art, and  FIG. 2  is a view showing the configuration of a conventional level gauge in accordance with the prior art. 
     Referring to  FIGS. 1 and 2 , the conventional level gauge includes a pipe (hereinafter, referred to as “tube”)  30  made of a metal material that is mounted on a swing decelerator  10  of a vehicle and a gauge part  50  that is accommmodatably joined to the tube to measure the level of oil. 
     The gauge part  50  includes a hand grip  53 , a sealing member  55 , and an inspection part  57 . 
     The hand grip  53  refers to a part that is gripped by an inspector&#39;s hand so that the inspector separates the gauge part  50  from the tube  30  to check the state of oil or couples the gauge part  50  to the tube  30 . The sealing member  55  refers to an element that allows the gauge part  50  to be securely fixed to the tube  30  and simultaneously hermetically seals the tube  30 . The inspection part  57  refers to an element that longitudinally extends inside an oil tank and allows for collection of an oil sample needed to check the state of the oil contained in the oil tank 
     In the above configuration, the inspector pulls up the hand grip  53  to separate the gauge part  50  from the tube  30 , and then identifies the state of the oil sample collected at a lower end of the inspection part  57  so that the inspector can check the state of the oil contained in the oil tank. 
     The gauge part  50  has concavo-convexes  56  formed on the outer circumferential surface of the sealing member  55  and the sealing member  55  is insertingly fitted into an upper end of the tube  30  in a press-fit manner. 
     However, the conventional level gauge entails a problem in that since the sealing member  55  is press-fittingly coupled to the tube, air inside the decelerator  10  is not easily discharged to the outside. In addition, the air inside the decelerator is expanded over time by heat generated in the operation process of the engine to cause the internal pressure of the engine to be increased, resulting in damage of a packing member or deterioration of operating efficiency of the machine. 
     Conventionally, in an attempt to solve such a problem, a discharge groove (not shown) is formed on the outer circumferential surface of the sealing member  55  in juxtaposition with the inner circumferential surface of the tube  30  so as to discharge the air heated to the outside through the discharge groove. However, such a conventional level gauge still encounters a problem in that foreign substances or moisture is introduced into the oil tank from the outside, resulting in deterioration of the quality of the oil and reduction of the lifespan of the machine. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Technical Problems 
     Accordingly, the present invention was made to solve the aforementioned problem occurring in the prior art, and it is an object of the present invention to provide a level gauge for checking the state and amount of oil, in which an air hole is formed on an outer circumferential surface of a tube disposed on a mechanical device such as an engine or a transmission of a vehicle, and a hole shield is formed at the outside of the sealing member fitted into an upper end of the tube to seal an inlet of the tube and shield the air hole so that the air inside the engine can be smoothly discharged to the outside and external foreign substances can be prevented from being introduced into the engine, and in which the level gauge and an oil injection port can be integrated into a single module, thereby reducing the manufacturing costs. 
     Technical Solution 
     To accomplish the above object, in accordance with an embodiment of the present invention, there is provided a level gauge that comprises a tube disposed on an engine of a vehicle and a gauge part accommodatably joined to the tube and configured to check the state of oil contained in the engine, 
     wherein the tube includes an air hole formed on an outer circumferential surface thereof so as to allow the air inside the engine to be discharged to the outside therethrough, and 
     wherein the gauge part includes: a sealing member insertingly fitted into an upper end of the tube and configured to hermetically seal the tube; a hole shield formed integrally with the sealing member and fitted around an outer circumferential surface of the tube to shield the air hole; and an inspection part joined at one end thereof to one side of the sealing member and longitudinally extending at the other end thereof to the inside of an oil tank. 
     Advantageous Effect 
     The level gauge in accordance with an embodiment of the present invention as constructed above has the following advantages. 
     Air expanded due to high temperature in the inside of the engine is smoothly discharged to the outside, and external foreign substances is prevented from being introduced into the engine, thereby extending the lifespan of the oil and the machine. In addition, the level gauge and the oil injection port can be integrated into a single module, thereby reducing the manufacturing costs. 
    
    
     
       BRIEF DESCRIPTION OF THE INVENTION 
       The above objects, other features and advantages of the present invention will become more apparent by describing the preferred embodiments thereof with reference to the accompanying drawings, in which: 
         FIG. 1  is a view showing the installation state of a conventional level gauge in accordance with the prior art; 
         FIG. 2  is a view showing the configuration of a conventional level gauge in accordance with the prior art; 
         FIG. 3  is a perspective view showing the configuration of a level gauge in accordance with one embodiment of the present invention; and 
         FIG. 4  is a cross-sectional view showing the configuration of a level gauge in accordance with one embodiment of the present invention; 
     
    
    
     PREFERRED EMBODIMENTS OF THE INVENTION 
     Now, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. The matters defined in the description, such as the detailed construction and elements, are nothing but specific details provided to assist those of ordinary skill in the art in a comprehensive understanding of the invention, and the present invention is not limited to the embodiments disclosed hereinafter. 
       FIG. 3  is a perspective view showing the configuration of a level gauge in accordance with one embodiment of the present invention, and  FIG. 4  is a cross-sectional view showing the configuration of a level gauge in accordance with one embodiment of the present invention. 
     Referring to  FIGS. 3 and 4 , the level gauge according to the present invention includes a tube  100  disposed on an engine of a vehicle and a gauge part  200  accommodatably joined to an upper end of the tube  100  and configured to check the state of oil contained in the engine. 
     The tube  100  is an element having a pipe shape that is mounted on a swing decelerator. The gauge part  200  is fixedly joined to an upper end of the tube  100 . The concrete shape of the tube and the state in which the tube is coupled to the engine are known in the art, and thus the detailed description thereof will be omitted to avoid redundancy. 
     The tube  100  includes at least one hole  150  formed on an outer circumferential surface of an upper portion thereof. When air inside the engine is thermally expanded, the air hole  150  allows air of the surplus volume to be discharged to the outside therethrough. The at least one air hole  150  is formed on the outer circumferential surface of the tube  100  at a position spaced apart by a predetermined distance from of the upper end of the tube  100 , so that the air hole  150  is not shielded by the sealing member  230  when the sealing member  230  which will be described later is insertingly fitted into the tube  100 . Thus, the air hole  150  is positioned at a position spaced apart from one side of the sealing member  230  in a state in which the sealing member  230  is insertingly fitted into the tube  100 . That is, a distance between the upper end of the tube  100  and the air hole  150  is set to be at least larger than that between the upper end of the tube  100  and an end of one side of the sealing member  230 . The sealing member will be described in detail later. 
     The gauge part  200  includes a sealing member  230  insertingly fitted into an upper end of the tube  100  to hermetically seal the tube  100 , a hole shield  250  formed integrally with the sealing member  230  and fitted around an outer circumferential surface of the tube  100  to shield the air hole  150 , an inspection part  270  joined at one end thereof to one side of the sealing member  230  and longitudinally extending at the other end thereof to the inside of an oil tank, and a hand grip  290  joined to the other side of the sealing member  230 . 
     The sealing member  230  has a shape corresponding to that of a hollow portion formed on an inner circumferential surface of the tube  100 . The sealing member  230  is inserted at one side thereof into the tube  100  and includes an extension portion  235  formed at the other side thereof. 
     Thus, the sealing member  230  is insertingly fitted into the tube  100 , the extension portion  235  serves as a retaining step so that the sealing member  230  is prevented from being completely inserted into the tube  100 . Generally, the tube  100  is formed in a cylindrical shape, and thus the sealing member  230  is also formed in a cylindrical shape corresponding to the shape of the tube  100 . 
     The sealing member  230  is insertingly fitted into the upper end of the tube  100  in a press-fit manner. Thus, generally, a plurality of concavo-convexes  233  is formed on the outer circumferential surface of the sealing member  230  so that a frictional force between the contacts surfaces of the sealing member  230  and the tube  100  can be minimized to allow the sealing member  230  to be easily coupled to and separated from the tube  100 . In addition, the outer diameter of above-mentioned concavo-convexes  233  is set to be larger than the inner diameter of the tube  100  so that the sealing member  230  can be press-fittingly coupled to the tube  100  to firmly seal the tube  100 . 
     The hole shield  250  is formed integrally with the sealing member  230  in such a manner as to have a cylindrical shape that is connected at one end thereof to the extension portion  235  of the sealing member  230  and downwardly extends at the other end thereof in juxtaposition with the outer circumferential surface of the sealing member  230 . In this case, a distance between the outer circumferential surface of the sealing member  230  and the inner circumferential surface of the hole shield  250  is set to correspond to the thickness of the tube  100 . Thus, when the sealing member  230  is coupled to the tube  100 , the sealing member  230  is fitted into the tube  100  and the tube  100  is inserted between the sealing member  230  and the hole shield  250  while the hole shield  350  shields the air hole  150  formed on the outer circumferential surface of the tube  100 . 
     The inspection part  270  is formed in a bar or cable shape that is joined at one end thereof to one side of the sealing member  230  and longitudinally extends at the other end thereof to the inside of an oil tank. The other end of the inspection part  270  is provided with a scale indicating a maximum point and a minimum point. The other end of inspection part  270  is partially submerged in oil contained in the engine when the sealing member  230  is coupled to the tube  100 . Thus, an inspector can remove the gauge par  200  from the tube  100  and observe the state of the oil to check the amount, the viscosity, etc., of the oil. That is, if the level of the oil adhered to the other end of the inspection part  270  is below the minimum point of the scale, the oil must be replenished. If the level of the oil adhering to the other end of the inspection part  270  approximates the minimum point of the scale, this means that the amount of the oil is sufficient. Further, if the oil sticking to the inspection part  270  is excessively discolored or the viscosity of the oil is degraded, the oil is replaced with new one. The inspection part  270  is an element that is known in the art, and thus the detailed description thereof will be omitted to avoid redundancy. 
     In the meantime, the gauge part  200  includes a hand grip  290  joined to the other side of the sealing member  230  so that a user can easily separate the gauge part  200  from the tube  100 . The hand grip  290  is generally formed in a loop or ring shape, but is not always limited thereto. The hand grip  290  may have any well-known various shapes that can be easily pulled up by a user&#39;s hand. 
       FIG. 5  is a perspective view showing the configuration of a gauge part of a level gauge in accordance with another embodiment of the present invention, and  FIG. 4  is a cross-sectional view showing the configuration of a level gauge in accordance with another embodiment of the present invention. 
     Referring to  FIGS. 5 and 6 , the level gauge in accordance with another embodiment of the present invention includes a tube  100  disposed on an engine of a vehicle and a gauge part  300  accommodatably joined to the tube  100  and configured to check the state of oil contained in the engine. The gauge part  300  includes: a sealing member  330  insertingly fitted into an upper end of the tube  100  and configured to hermetically seal the tube  100 , the sealing member  230  including an extension portion  335  formed at one side thereof; a discharge groove  310  longitudinally formed extending from an end of the other side of the sealing member  230  to the extension portion  335  formed at the one side of the sealing member  230 ; a shield  350  formed integrally with the sealing member  330  in such a manner as to be spaced apart from an outer circumferential surface of the tube  100 ; and a filling member  360  disposed on the inner circumferential surface of the shield and configured to fill a space defined between the tube  100  and the shield  350 . 
     The discharge groove  310  is formed longitudinally along the outer circumferential surface of the sealing member  330 . In this case, the discharge groove  310  extends from an end of the other side of the sealing member  230  to the extension portion  235  formed at the one side of the sealing member  230 . 
     The shield  350  has a cylindrical shape that is formed integrally with the extension portion  335  of the sealing member  230  to surround the outer circumferential surface of the upper portion of the tube  100 . In this case, the inner circumferential surface of the shield  350  is not brought into close contact with the outer circumferential surface of the tube  100  but is formed spaced apart by a predetermined distance from the outer circumferential surface of the tube  100 . 
     The filling member  360  is disposed on the inner circumferential surface of the shield and serves to fill a space defined between the tube  100  and the shield  350 . In this case, the filling member  360  is made of a porous material having a fine pore size, such as sponge or cork so that leakage of the oil contained in the engine or introduction of external foreign substances into the engine can be prevented and simultaneously the air expanded in the engine can be discharged to the outside. The filling member  360  may be disposed between an upper end of the tube  100  and the extension portion  335  depending on the needs. The filling member  360  made of the porous material may use known various materials, and thus the detailed description thereof will be omitted to avoid redundancy. 
     The constitution of the gauge part of the level gauge in accordance with another embodiment of the present invention are the same as that of the gauge part of the level gauge described in  FIGS. 3 and 4  except the discharge groove  310 , the shield  350 , and the filling member  360 . In addition, the constitution of the tube  100  of the level gauge in accordance with another embodiment of the present invention is the same as that of the tube described in  FIGS. 3 and 4  except that the tube  100  does not include the air hole formed thereon. Thus, the description of the constitution of the gauge part and the tube, which is the same as that described in  FIGS. 3 and 4  will be omitted. 
     In the above constitution, the level gauge in accordance with another embodiment of the present invention allows the air expanded in the engine to be moved to the extension portion  335  of the sealing member  330  along the discharge groove  310  and then discharged to the outside while passing through the filling member  360 . In this case, the filling member  360  made of a porous material having a fine pore size allows a gaseous material such as air to easily permeate therethrough when a predetermined pressure is reached, but does not allow liquid or solid foreign substances to permeate therethrough. 
     While the present invention has been described in connection with the specific embodiments illustrated in the drawings, they are merely illustrative, and the invention is not limited to these embodiments. It is to be understood that various equivalent modifications and variations of the embodiments can be made by a person having an ordinary skill in the art without departing from the spirit and scope of the present invention. Therefore, the true technical scope of the present invention should not be defined by the above-mentioned embodiments but should be defined by the appended claims and equivalents thereof. 
     INDUSTRIAL APPLICABILITY 
     As described above, the present invention relates to a level gauge, and is applied to the manufacture of a level gauge that is disposed on a mechanical device such as an engine or a transmission of a vehicle so that air inside the engine is discharged, introduction of foreign substances into the engine is prevented, and the level gauge and an oil injection port can be integrated into a single module, thereby reducing the manufacturing costs.